Panel surge protector in garage

[scoob8000]

I posed this question in a different forum and got some varying answers. I want to see what you all think.

My garage panel is a sub-panel off the house fed with 2-2-4-6 MHF. The neutral and ground bars are not bonded at the garage.

I have 2 8' rods driven at opposite corners of the garage, and tied back to the ground bus with #6 copper.

I bought a Square D surge protector for the garage. Directions state to connect to HOT-HOT-NEUTRAL. My thoughts are to connect to the ground instead of neutral since the ground would be lower impedance than going all the way back to the house via the neutral wire.. A call to Square D confirms that connecting to ground would be acceptable, and perhaps even better in this application.


What are your thoughts?

 

[malibu101]

My thoughts are listen to what the manufacturer told you.

 

[gregtwojeeps]

Very unlikely that a SP unit if it has a white colored wire ....should be hooked to anything but the neutral bus in my opinion. How many and what color wires does your SP unit have ? Is it a ****** mount, breaker type, or a separate TVSS enclosure ?

 

[redmondjp]

I would follow the instructions as well. The device will be most beneficial connected between line and neutral, as that is the potential difference that everything connected will see - you want to limit this potential to a safe level.

 

[sberry]

Its prolly sposed ro be connected to main. If it was on a 4 wire sub would also consider ground bar.

 

[westom]

I bought a Square D surge protector for the garage. Directions state to connect to HOT-HOT-NEUTRAL. My thoughts are to connect to the ground instead of neutral since the ground would be lower impedance than going all the way back to the house via the neutral wire.

Every incoming wire must connect together in a low impedance connection. That means all four wires. If any wire (including telephone or cable) enters without a low impedance earthing connection, then protection is compromised.

Neutral must connect to earth ground via a low impedance connection either directly (as found in the mains box) or via a protector (when neutral and safety ground are separate.

An earthing connection for any separate building must be a single point earth ground. If that neutral wire does not connect to earth via a protector, then earth ground for that neutral is a different electrode. That means voltage on sub-panel neutral would be significantly different from other wires - during a surge.

Was Square D support specifically told that safety ground and neutral are separate? A significant fact often overlooked by tech support that assumes a protector will only be used in a mains box - not in a sub-panel. Or that assumes sub-panel is wired differently - ie only three AC wires (2 hot, 1 neutral). Second sub-panel is wired similar to a mains box with a required earth ground connection. Did he know the difference? A Square D protector is sufficient for this second type sub-panel.

A simple rule applies. If any incoming wire does not connect low impedance to single point earth ground, then protection is compromised.

A cow, killed by lightning, demonstrates this. Lightning strikes a nearby tree. A cow 10 meters away is killed. Lightning is a connection from cloud to distant earthborne charges. Connection is three kilometers down to a tree and maybe four kilometers through earth to charges. That path also went up the cow's hind legs and back to earth via fore legs. Because fore and hind legs were separate ground connections, then a cow is killed.

You have same. Earth electrode for a main building is completely different from an electrode for the garage. A current up hind legs (main building electrode) returns to earth via fore legs (garage appliances and garage earth electrode).

Learn science from someone who did this stuff - not from anyone who makes recommendations without learning fundamental reasons why. Most who make recommendations (such as some here) never first learned how and why a 'system' works. Any recommendations without explaining the science should be immediately discounted. Apparently you are not doing that. Discounting may eliminate most recommendations.

Any incoming wire not connected low impedance to a single point earth ground means compromised protection. Technology is that simple. And completely unknown to many who will still make recommendations.

 

[wyliesdiesels]

Wow what a surprise. Westom is back!

 

[sberry]

Good.

 

[sberry]

I like the fact you include phone here.

 

[Rookie2]

So , Do you have a similar protection in your main house panel ? Why not ? also there is no sense in wiring them to a circuit breaker unless they specify the breaker or are installed into two spare slots.

http://www.garagejournal.com/forum/showthread.php?t=288684&highlight=surge+protection

 

[sberry]

The surge should go to the rod on a detatched structure. Ideally there should be one on the main with it at N/G and one on a service from an existing service to a detatched structure.
I have some notes from someone with a mind way greater than my own nursed me along the same lines as westom lays out. He used a parking lot light as an example. You still need the ground wire but adding a rod helps from a strike as we really don't want it carried on the service wire back to where it originates,,,, much rather have it go to ground right at the pole,,, same for main/sub and PHONE BEFORE it enters the building. This was a huge problem with old dial modems, they were a pathway to your grounded computer.

 

[gregtwojeeps]

Every incoming wire must connect together in a low impedance connection. That means all four wires. If any wire (including telephone or cable) enters without a low impedance earthing connection, then protection is compromised.

Neutral must connect to earth ground via a low impedance connection either directly (as found in the mains box) or via a protector (when neutral and safety ground are separate.

An earthing connection for any separate building must be a single point earth ground. If that neutral wire does not connect to earth via a protector, then earth ground for that neutral is a different electrode. That means voltage on sub-panel neutral would be significantly different from other wires - during a surge.

Was Square D support specifically told that safety ground and neutral are separate? A significant fact often overlooked by tech support that assumes a protector will only be used in a mains box - not in a sub-panel. Or that assumes sub-panel is wired differently - ie only three AC wires (2 hot, 1 neutral). Second sub-panel is wired similar to a mains box with a required earth ground connection. Did he know the difference? A Square D protector is sufficient for this second type sub-panel.

A simple rule applies. If any incoming wire does not connect low impedance to single point earth ground, then protection is compromised.

A cow, killed by lightning, demonstrates this. Lightning strikes a nearby tree. A cow 10 meters away is killed. Lightning is a connection from cloud to distant earthborne charges. Connection is three kilometers down to a tree and maybe four kilometers through earth to charges. That path also went up the cow's hind legs and back to earth via fore legs. Because fore and hind legs were separate ground connections, then a cow is killed.

You have same. Earth electrode for a main building is completely different from an electrode for the garage. A current up hind legs (main building electrode) returns to earth via fore legs (garage appliances and garage earth electrode).

Learn science from someone who did this stuff - not from anyone who makes recommendations without learning fundamental reasons why. Most who make recommendations (such as some here) never first learned how and why a 'system' works. Any recommendations without explaining the science should be immediately discounted. Apparently you are not doing that. Discounting may eliminate most recommendations.

Any incoming wire not connected low impedance to a single point earth ground means compromised protection. Technology is that simple. And completely unknown to many who will still make recommendations.

Very impressive read, but I apologize now beforehand to the readers now for posting the following windy post but.... I take just a tad bit of offense to the blue text above, but I am not a forum "groupie" to anyone on GJ ....

The above post would probably be more suited for a electrical engineering class/votech school than for a DIYer on a garage forum ....when a DYI'er is asking about how to wire up his SP. The folks that ask questions on here to get help with their projects are not master electricians or engineers, if they were ...why would they be posting on a garage topic based forum ???

Yes sir, would it not be great, if that everyone that bought a piece of electrical equipment knew every aspect of why it was built, how the manufacturer derived its design configuration, knew how every small component inside of it was designed to perform a particular function and even knew the scientific formula's the engineers used to derives those manufacturing specifications ??... .

But out here in the real world where people install electrical equipment very day, they do not have to know the complete engineering aspect of EXACTLY how every component works.... they are installing. The equipment manufacturer's engineering staff has worked out all of those details and THEY know better than anyone else, how their piece of equipment should be installed...

Therefore, the equipment manufacturer's do not put a book with their equipment when it is sold to the customer.... that gives all of the scientific details as to how their equipment works. They do not need to, as they have sales/service representatives on payroll trained to find the answers to all engineering /installation questions the customer may have for them. They want it that way, equipment failures due to installer error in the end, usually just makes their product look bad by virtue of that bad news spread faster than good, and it is never the customer's fault...as they say. Plus, no manufacturer wants to end up in litigation, from a improperly installed piece of equipment they sold...


What has been failed to be mentioned in the above post while admonishing the posters that have contributed to this thread ...is that most likely we are not engineers or a SP/TVSS expert such as Westom may be..

Anytime any piece of electrical equipment that is not wired or installed in compliance with the manufacturer's instruction's, the installer bears the responsibility for the failure of said equipment, the damages suffered to property or life, by that failure. .Simply by not adhering to the written or oral instructions from the equipment manufacturer's manual or representative, they instead chose to "wing it " and get some "on line" folks or some buddies advice, so they wire the equipment as advised and it fails. ....

So at the time of my typing this we now have, without even knowing the type of SP ( I asked, but still no answer from the OP as his SP could be a ****** mount, breaker type, or even a seprate enclosure TVSS) the assumption now is, the OP has a SP that has only has 3 wires...two blacks and a white ? There are various brand SP's that have two blacks, a white and green conductor we know . ...

So, if it is a 4 wire SP and the OP attaches the white ( neutral) wire to the bare ground conductor along with the green, what would that wiring configuration say to you ? That just maybe inside of the SP is a component that requires a neutral conductor and the SP manufacturer installed a neutral wire just for that function.... then along with a green conductor to be hooked to the earth ground ?

And what has also been failed to mention, is that these "tapped on " SP's are at the bottom of the barrel for true TVSS protection. The only SP/TVSS worth its salt is one where the main service conductors go THROUGH the TVSS and then the service conductor's exit the TVSS to be hooked to the panel board's main bus. Yes, they are more $$$. ...

These "taps on" SP's are cheaper and will catch some of the spikes, transients currents MAYBE... before they get out to the equipment on the same bus or breaker they are wired to. But they will not catch offending power ..like a feed through TVSS unit will . I would take a SP protected electrical outlet that the appliance / equipment plugs in to..... over a main buss tap type SP. At least one knows the offending power coming in will have to go through the SP at the point of use... before it goes in to the equipment ..

Maybe I need to buy one of those keyboards that has the satellite camera on it.... that can see exactly what the equipment looks like the posters are asking about out here on the spider WEB. That would sure as hell make it easier for people in trying to answer their questions, when folks will not post pictures or links of what equipment they are asking about or wiring up. All JMO and

 

[wyliesdiesels]

Westom has a history of talking down to people with a holier than thou and i know more than you type of attitude while saying they dont know what theyre talking about. While at the same time he will say to do things that are wrong or not to code. Several people have taken the time to post white paper references that fly in the face of what he claims to be correct. When they post the references he ignores them and wont respond to the issues brought up.

When people ask him to provide references, he wont give them. But will continue with the diatribes!

Do a search for threads he comments on and you will see what Im talking about.

Also, he only seems to know about grounding when it comes to lightning. He wont comment on any other type of threads...

 

[rlitman]

And what has also been failed to mention, is that these "tapped on " SP's are at the bottom of the barrel for true TVSS protection. The only SP/TVSS worth its salt is one where the main service conductors go THROUGH the TVSS and then the service conductor's exit the TVSS to be hooked to the panel board's main bus. Yes, they are more $$$. ...

I would take a SP protected electrical outlet that the appliance / equipment plugs in to..... over a main buss tap type SP. At least one knows the offending power coming in will have to go through the SP at the point of use... before it goes in to the equipment ..

BS. Such utter BS in fact that I feel the need to call you on this one. Westom is 100% in the right.

If you understood Kirchoff's law, you would understand why there is no such thing as a pass-thru TVSS. Regardless of how it is mounted or wired, all that matters is the impedance to it, and it's impedance to ground. Surprisingly, even the wire gauge to it does not matter as much as you would expect (and the rating of the breaker is is connected through is pretty much immaterial).

Attached is a photo of a TVSS (the best money can buy from Square D), spec'd specifically by Schneider (the parent of Square D) engineers for a custom engineered (also by Schneider) 2500A service entrance.
No conductors go THROUGH it. It contains three potted (for safety) TVSS modules inside, for both phase-to-phase and phase-to-ground protection.

 

[rlitman]

Any incoming wire not connected low impedance to a single point earth ground means compromised protection. Technology is that simple. And completely unknown to many who will still make recommendations.

Exactly. A TVSS with three wires is not appropriate for a sub panel without a neutral-ground bond.

 

[sberry]

Westom has a history of talking down to people with a holier than thou and i know more than you type of attitude while saying they dont know what theyre talking about. While at the same time he will say to do things that are wrong or not to code. Several people have taken the time to post white paper references that fly in the face of what he claims to be correct. When they post the references he ignores them and wont respond to the issues brought up.

When people ask him to provide references, he wont give them. But will continue with the diatribes!

Do a search for threads he comments on and you will see what Im talking about.

Also, he only seems to know about grounding when it comes to lightning. He wont comment on any other type of threads...

Did you contribute 5 cents worth here?

 

[wyliesdiesels]

Did you contribute 5 cents worth here?

Yes i did.

Im not gonna argue with him anymore.

On other threads hes told me that i dont know anything or tries to say that my experiences are wrong or i dont know what im talking about.

When ive pointed out some wiring methods, that he said to do, were against code, he blew me off.

He has called others wrong and told them they know nothing. Dont believe me? Do a search.

I will say this. He does know some things and not everything he says is wrong. But his condenscending attitude towards others is not warranted.

 

[gregtwojeeps]

BS. Such utter BS in fact that I feel the need to call you on this one. Westom is 100% in the right.

If you understood Kirchoff's law, you would understand why there is no such thing as a pass-thru TVSS. Regardless of how it is mounted or wired, all that matters is the impedance to it, and it's impedance to ground. Surprisingly, even the wire gauge to it does not matter as much as you would expect (and the rating of the breaker is is connected through is pretty much immaterial).

Attached is a photo of a TVSS (the best money can buy from Square D), spec'd specifically by Schneider (the parent of Square D) engineers for a custom engineered (also by Schneider) 2500A service entrance.
No conductors go THROUGH it. It contains three potted (for safety) TVSS modules inside, for both phase-to-phase and phase-to-ground protection.

You are right about the TVSS wiring and I stand corrected as I used the wrong verbiage. The panel boards main service conductors do NOT go through the TVSS, the TVSS conductors goes through the panel board cabinet and tap on to a breaker or busbars. To the rest of your reply above, I will reciprocate in like kind, as you have replied to me.


Apparently you misunderstood me as some one that gives a damn about what you or Weston knows about surge protection. Weston may be 100% right about his Theory of Operations on the science of TVSS and surge protection, and I never said he was wrong. I stated in my long post above that he is just guilty of doing what so many GJ people do on these forums as you are doing now.... going in way too deep for a DIY'er on a garage forum. I'll repeat myself now , as you seem to not get the crux of my post above. Do think master electrician's and engineers come to a GARAGE FORUM to get electrical help ?

The OP simply asked if the white wire of his SP went on the earth ground of a garage subpanel. And I state AGAIN, Weston did not even know what SP the OP owned, did not even ask him how many conductors his SP had.... and instead he gave the forum the last rites on the science of TVSS and spoke "down" on everyone that had replied to this thread. You and Weston may know your electrical theories, but neither one of you know **** about how to talk to people that ask for help.....

This is the second time you have attacked me personally Rlitman. Rather than you simply questioning my posts for accuracy as to allow for a civil discourse or any corrections on my part, you choose to open your replies to my posts by stating that first... I am full of ******** and then continue on with some condescending remark. . ...

The stage for civility in any conversation is set in the first two words and apparently ....you have a damn narrow vocabulary. So rather than me taking the chance of getting banned on our next exchange, you are going to be the very first and only.... person on my ignore list. Please reciprocate to me in like kind.

 

[rlitman]

This is the second time you have attacked me personally Rlitman.

You must be keeping some sort of score here. I do not ascribe to that practice, but you are free to interpret my posts however you like, so I'll take you at for word for this being a second time. I did not mean to offend, but I admit that I can get offended by misleading information being posted...

As I see it, you went off on a nonsensical diatribe on another member's completely correct (though wordy) posting. I'll leave it at that. The information should stand on its own.

My point (and really the only point I am trying to make in this thread) is that the OP purchased a TVSS that is inappropriate for his setup, and any suggestions as to how to shoehorn it into working as he desires will lead the OP into a false sense of security. And the crux of the misinformation above is from people who believe that wire colors and manufacturer's instructions impart magical properties that allow them to defy the laws of physics. Imagine if you will someone making a well meaning suggestion that the only appropriate brake hose to ever be used in any situationis a DOT rated hose, and then trying to apply that advice to an aircraft.

 

[westom]

The above post would probably be more suited for a electrical engineering class/votech school than for a DIYer on a garage forum ....when a DYI'er is asking about how to wire up his SP. The folks that ask questions on here to get help with their projects are not master electricians or engineers, if they were ...why would they be posting on a garage topic based forum ???

Posted was vastly simplified to a layman's level. Underlying engineering concepts were only summarized; not included. These simple concepts must be appreciated to properly install that solution.

That a hardwire cannot have sharp bends - is that also too advanced for a layman?

No one was 'talked down' to. Anyone who recommends without 'reasons why' is demeaning others. Exposed were recommendations made without technical knowledge. Responsible recommendations always state 'reasons why' a recommendation is valid. Knowing why is essential to know which answers are valid and which are only hearsay. Also needed to properly install the solution.

For example, an informed layman can recommend a fuse or wall receptacle. Amperage or a 'two vs three wire' receptacle selection does not require an engineering degree. A "I always install three prong receptacles and have no problems" without knowing 'when and why it is acceptable' is also irresponsible. It deserves strong condemnation. That example (made without learning simple layman concepts) demonstrates contempt for peers and human life.

Layman level 'reasons why' were included so that a reader can separate bogus lies from responsible sources. Bogus answers say what to do; never say why and do not cite relevant numbers. Exposing it was never demeaning. Every adult needs 'reasons why'. Or eventually learns the hard way from a resulting disaster.

A critical concept is low impedance. Others expanded on this concept; making useful contributions. For example one noted that wire gauge is little relevant. Shorter wire (not thicker wire) mostly defines lower impedance. Additional layman 'reasons why' were provided. All were relevant and informative. None required more than a high school education - were that layman simple.

A useful answer would have said why a three wire protector is acceptable on four incoming power wires. Nobody does for one reason. It is neither effective nor acceptable. Replies that discussed simple 'hows and whys' followed. Noted by others was that an earth ground electrode must connect low impedance to all incoming wires.

No attitude exists. Technically challenged was hearsay presented as if informed fact. Others also discuss what is relevant - a low impedance connection to an earthing electrode. Bogus myths were separated from informed replies by simply demanding 'reasons why'. All provided 'reasons why' are layman simple concepts. Nothing required an engineering or vo-tech degree.

 

[westom]

And what has also been failed to mention, is that these "tapped on " SP's are at the bottom of the barrel for true TVSS protection. The only SP/TVSS worth its salt is one where the main service conductors go THROUGH the TVSS and then the service conductor's exit the TVSS to be hooked to the panel board's main bus. Yes, they are more $$$.

So you believe a protector will somehow block a destructive surge? A surge is a constant current. That means voltage will increase as necessary to maintain that current; may blow through that 'THROUGH the TVSS' protector.

Telco COs suffer about 100 surges with each storm. How often is your town without phone service for four days while they replace that $multi-million computer? Never? A 'through the TVSS' protector is not used. Instead a 'tapped on' protector is attached to every wire inside every incoming cable. More important is what does protection - a low impedance connection to earth.

Surges are never blocked (as you have assumed). A surge that connect low impedance to earth (without passing into a building) does no damage. Telcos all over the world suffer about 100 surges at each facility without damage. Why do they not do what you recommend? Because they know what any layman can (or eventually will) learn. A protector is only as effective as its earth ground. That has been a best and proven solution for over 100 years.

 

[sberry]

There isn't anything above most heads here and I like the explanation and I do agree I don't need every engineering detail some explanation helps basic understanding of fundamentals. My Telco does a **** job of installer training, they ride them around in a truck for a bit and turn them loose. I don't think any of them spent a day in class and certainly never read 880
I remember doing mine and asked a code guru and mentioned the length would be greater and that I would upsize for it and he mentioned that he would take it with the listed wire which I believe is an insulated 14.
In some sense of the theory the lead would be best bugged on the rod wire and may be better than the bar itself.

 

[scoob8000]

Wow. I apologize for not replying back sooner. It's been a busy week.

The protector in question is a 3 wire type (2 black, 1 white wire). It is a type 1 ****** mount style.

I do actually have a protector at the main panel in the house as well. It is a 4 wire, type 2. I went with the Square D unit for the garage because it was readily available.

And when I contacted Square D support, it was perfectly understood by them this is a sub-panel, and the neutral is not bonded to the ground.

 

[westom]

My Telco does a **** job of installer training, they ride them around in a truck for a bit and turn them loose. I don't think any of them spent a day in class and certainly never read 880

Their phone would ring once. Then the caller was disconnected - immediately got a dial tone. Four techs each tried to fix it. Each saw the problem; had no idea of the 'reasons why'. Then a veteran arrived. He discussed those 'three week wonders' that were suppose to be his equivalents (according to business school graduates and their spread sheets). He fixed that problem in minutes by simply replacing a telco 'installed for free' protector.

Same problem is found in the welding industry. Now that costs (rather than the product) are more important, companies do not spend money training their employees. "If we train them, then they will goes elsewhere for higher pay." Duhhhh. When your welder is more productive, then he must be paid more. That means costs decrease and profits increase - contrary to what is taught in business schools.. So many welding companies no longer train. Then, of course, they cannot find qualified welders.

A problems observed where business school graduates replace people who know how the work gets done. Just because a phone jockey answers phones for Square D does not mean he knows anything about four wire products. Why do we know? Did he say why a three wire protector does same as a four wire? How did he expect a fourth wire to connect to earth? Both are damning questions. Did he say that was just fine without any 'reasons why'? Many who disagree with that phone jockey also include what he did not provide: the 'always required' reasons why. Why does a three wire protector do same as a four wire? What was his reasoning?

Demonstrated is an increasing domestic problem - employees now get less to no training. How do you know? He only tells you what to believe - never says why.

No engineering details were posted here. What were assumed to be engineering details are only layman concepts - summaries. Nothing was sufficient to design anything. Only defined is what must connect to what - with soundbyte expressions such as low impedance. Everything here is layman-ized. That Square D tech displays classic symptoms of a 'three month wonder'. Apparently he tells you what to believe without any reasons why. That is only sufficient for a consumer who all but wants to be brainwashed.

Informed consumers ignore recommendations that do not also say why. Especially now that America has an increasing number of 'three week wonders'.

BTW, insulated 14? Do you mean 14 AWG? Increasing to 12 or 10 would not lower impedance. Resistance is lowered by increasing wire diameter. Same does almost nothing to decrease impedance. No engineering details are provided. Described is a layman concept that 'dumbs down' a complex engineering detail. You should know that increasing wire diameter does a near zero impedance reduction. Removing every foot of wire length DOES reduce impedance. Company training should have explained that.

 

[kaffine]

I would say the best option would be to take the 4 wire one off the main and put it on the garage and put the 3 wire on the main if possible. As the main has the neutral and ground bonded there is no need for a TVSS protection between neutral and ground so the 3 wire one will be fine in the main.

If using the 3 wire SP on a sub with isolated ground and neutral put the white wire on the neutral not ground.

Equipment will be damaged by overvoltage on line to line if 240V or line to neutral for 120V loads more than a difference between ground and line or ground and neutral. Therefore you want the TVSS on the line and neutral connections. As it is those voltages that are going to be what damages equipment.

Yes you can get enough of a voltage difference between line and ground for it to arc over in the equipment and cause damage. That voltage difference however will be well above the level required for damage for a overvoltage between line and neutral.

 

[sberry]

Westom gave bit more here and I had originally wondered why the guru said what he said. There is some length discussed in the code provision about using the available rod or uffer or pounding a rod. I mentioned I was further and he said, no prob and would have bought it without the upsize and I could essentially bury it along the foundation to the rods,,, s about as good as it got.
I also had a steel well case project and the instruction was to clamp the service ground to the casing, I said 1 better will weld a lug on and not to use suplimentary rods in that case.
He wants to give the strike no choice in the matter.

 

[sberry]

I believe most protection is cabled external etc. No 100% deal but cant hurt to keep it outside the structure.

 

[zmaxmotorsports]

Posted was vastly simplified to a layman's level. Underlying engineering concepts were only summarized; not included. These simple concepts must be appreciated to properly install that solution.

That a hardwire cannot have sharp bends - is that also too advanced for a layman?

No one was 'talked down' to. Anyone who recommends without 'reasons why' is demeaning others. Exposed were recommendations made without technical knowledge. Responsible recommendations always state 'reasons why' a recommendation is valid. Knowing why is essential to know which answers are valid and which are only hearsay. Also needed to properly install the solution.

For example, an informed layman can recommend a fuse or wall receptacle. Amperage or a 'two vs three wire' receptacle selection does not require an engineering degree. A "I always install three prong receptacles and have no problems" without knowing 'when and why it is acceptable' is also irresponsible. It deserves strong condemnation. That example (made without learning simple layman concepts) demonstrates contempt for peers and human life.

Layman level 'reasons why' were included so that a reader can separate bogus lies from responsible sources. Bogus answers say what to do; never say why and do not cite relevant numbers. Exposing it was never demeaning. Every adult needs 'reasons why'. Or eventually learns the hard way from a resulting disaster.

A critical concept is low impedance. Others expanded on this concept; making useful contributions. For example one noted that wire gauge is little relevant. Shorter wire (not thicker wire) mostly defines lower impedance. Additional layman 'reasons why' were provided. All were relevant and informative. None required more than a high school education - were that layman simple.

A useful answer would have said why a three wire protector is acceptable on four incoming power wires. Nobody does for one reason. It is neither effective nor acceptable. Replies that discussed simple 'hows and whys' followed. Noted by others was that an earth ground electrode must connect low impedance to all incoming wires.

No attitude exists. Technically challenged was hearsay presented as if informed fact. Others also discuss what is relevant - a low impedance connection to an earthing electrode. Bogus myths were separated from informed replies by simply demanding 'reasons why'. All provided 'reasons why' are layman simple concepts. Nothing required an engineering or vo-tech degree.

Can you repeat all of that in simple english?

 

[rlitman]

I would say the best option would be to take the 4 wire one off the main and put it on the garage and put the 3 wire on the main if possible. As the main has the neutral and ground bonded there is no need for a TVSS protection between neutral and ground so the 3 wire one will be fine in the main.

That's what I would do. A type I SPD will work fine connected to a breaker in the main panel. And the type II SPD will work fine connected to a breaker in the sub.

The advantage of a type I, is that it has built-in overcurrent protection (usually potted fuses inside) so it can be used in a location that does not offer overcurrent protection (such as in a meter pan), but when replacing an SPD in a main panel, you can always plug a type I SPD into the same breaker when replacing a type II.

 

[DC73]

Posted was vastly simplified to a layman's level. .

No it wasn't. Once again, you've displayed a complete lack of ability to simply answer a question and then explain the reasons and science behind it in a way a layman could grasp. Wylie is right about you.

DC