Creating a traditional isolated ground

[Teken]

Sparkies: What are the steps in creating a isolated ground in residential home setting?

Are there procedures to keep in mind and faults to consider?

Insight . . .

 

[mrb]

if fed from the main panel dedicated run with romex then you already have IG.

 

[Teken]

if fed from the main panel dedicated run with romex then you already have IG.

If a person was to install three grounding rods say in a attached garage using the dedicated circuit outlined above.

Would this cause a ground loop, or cause other negative affects to the attached equipment?

 

[ddawg16]

Not sure where your headed...but....there are a couple of issues to take into consideration....

Your neutral is connected to ground in only one spot....where you power comes in. If you have a sub panel in the garage, you do NOT connect the earth to the neutral in there....but you do tie that sub panel to the earth ground from the main panel....and should also have a ground rod or two at the garage.

Having multiple grounds does not create a ground loop in that in practice, there should be no current to ground assuming all is connected and working correctly. However, if you tie the neutral in the garage to the earth ground there....now you have a 'ground loop'.

When you tie the neutral in the main panel, what your really doing is just setting the reference level for the neutral.....as well as everyone around you who is on the same transformer....and their connection from neutral is also setting a reference level.

Initially, this would seem to contradict why you don't ground your neut in the sub panel. One would think that if 2 or more houses have their neut tied to earth (parallel) connections, then it would not matter if your house does the same. The issue is that your not connected to the other house.

Man....this is complicated to explain....I really need a napkin to show you how it works...

So, back to the original issue...drive in as many ground rods as you want....your neut is only connected in one place.

 

[mrb]

i dont know where you would have to connect your extra ground rods, but you do realize that both the isolated ground and equipment ground get connected together right?

I have seen a couple scary IG installs where the installer didnt understand how such a systems works and the IG was connected to ground rods only. this is dangerous as it leaves you with no path for fault current.

if you want an isolated ground off a subpanel, you need a 5th wire between the subpanel and the main, and the subpanel gets a 2nd neutral bar not bonded to the can, this is your isolated ground bar, the 5th wire connects this to the ground bus at your main. then you have 4 wires to the IG receptacle Hot, Neutral, EG (green), IG (green/yel).

I dont really know what this setup is going to do for lightning, the purpose of it was to get rid of problems with ground loops in old non-differential computer networks and terminals (thicknet, stuff with BNC connectors) and is used sometimes in A/V usually only because the installers dont really understand whats going on and demand orange IG receptacles. You usually lose the isolation once stuff gets plugged into the receptacles anyways. (ex had a sound system install where audio guys demanded IG for the amps. Fine, but the entire racks were at IG through the chassis of the amps so those had to be isolated from touching any other building metal. I recieved great joy showing them how their 5 or 10k extra they spent on IG went out the window when the audio signals from foh got plugged into the amp room)

 

[41ratrod]

So lets get this right if you got a sub panel in the garage you shouldn't
have a ground rod -ground wire connected to the neutral bar, the neutral
should not be grounded to the box. And use another bar for the grounding.
But is it ok to use a ground rod as long it is NOT hooked to the neutral bar.

 

[mrb]

So lets get this right if you got a sub panel in the garage you shouldn't
have a ground rod -ground wire connected to the neutral bar, the neutral
should not be grounded to the box. And use another bar for the grounding.
But is it ok to use a ground rod as long it is NOT hooked to the neutral bar.

no. if you were responding to my post, the 2nd neutral bar isnt a neutral bar its used as an isolated ground bar. you use a neutral bar for this because the IG shouldnt be connected to the can of the subpanel only to the location of the main bonding jumper at the service.

this might help http://www.electrical-contractor.net/theory/igopt2.gif

 

[mrb]

Note to all: keep in mind what is being discussed here is Isolated Ground where the ground pin of a special receptacle has its own insulated path back to the service. This is not the same use of the term isolated you see us use in regard to neutral bus bars in subpanels. Do not pay attention to anything here if you are trying to figure out how to do any normal residential wiring, hook up a subpanel, ground rods, or anything of the sort. This isnt that.

 

[sberry]

Agreed and well put. As you said, keep it simple and if a guy is heart set on IG in a residential setting run a romex back to the main and mount recept in a plastic box, this is ideal for electronics in older homes, dedicated new circuit and about as good as it can get.

 

[sberry]

I am a member of Buckley Old Engine Show, I call it the old junk show but its good for business. A ton of infrastructure and volunteer labor. Unlike a lot of this type of thing it is very well run and the labor pool as well as some dedicated members (lots of retired and semi retired) is way above the average bears in competency and expertise as well as general skill. Very well organized within depts, building, elect, plumbing. I ask the guy a while back for a couple circuits and I know before I even talk to him that he is head electric insp from the next county over. I live and let live with this one but he started to ask some details and I say, 6-50-R, min 10 wire 50 ocpd, he thought, looked at me for a spit second,, I smile and say,, I know the difference between the green and the white,,, he laughs and off he goes. Sometimes its all you need to say to the guy.

 

[mrb]

...............nevermind

 

[theoldwizard1]

Note to all: keep in mind what is being discussed here is Isolated Ground where the ground pin of a special receptacle has its own insulated path back to the service.

Very true !

Another way to think of isolated ground is insulated ground. That is, the wire going back to panel is completely insulated. The only possible way it can contact another ground is at the junction in the panel box which is bonded with the neutral at that location.

As mrb stated,, you must use special receptacles (orange or if hospital, then white with an orange delta symbol). These receptacles do NOT connect the ground to the mounting bracket and screws.

The only place I have seen them is in computer rooms (and boy have I seen a lot of them there).

 

[Teken]

Very true !

Another way to think of isolated ground is insulated ground. That is, the wire going back to panel is completely insulated. The only possible way it can contact another ground is at the junction in the panel box which is bonded with the neutral at that location.

As mrb stated,, you must use special receptacles (orange or if hospital, then white with an orange delta symbol). These receptacles do NOT connect the ground to the mounting bracket and screws.

The only place I have seen them is in computer rooms (and boy have I seen a lot of them there).

This is indeed for a communication center being built . . .

 

[kaffine]

Well if you really want to know about comm site grounding get a copy of Motorola R56.

What kind of gear are you going to be using? If computer equipment I wouldn't worry about the equipment itself just make sure all external comm lines have good TVSS that are properly grounded. Assuming you have grounded outlets to begin with. I would put in dedicated outlets for the equipment instead of isolated grounds if you really want but unless you have enough equipment that you need more power anyways I wouldn't go to the trouble.

Now if you are talking radio equipment with a tower then that will require better grounding.

 

[Teken]

Well if you really want to know about comm site grounding get a copy of Motorola R56.

What kind of gear are you going to be using? If computer equipment I wouldn't worry about the equipment itself just make sure all external comm lines have good TVSS that are properly grounded. Assuming you have grounded outlets to begin with. I would put in dedicated outlets for the equipment instead of isolated grounds if you really want but unless you have enough equipment that you need more power anyways I wouldn't go to the trouble.

Now if you are talking radio equipment with a tower then that will require better grounding.

It will be a combination of radio, cellular, cable, telco fiber, and server related gear.

Dedicated circuits all with secondary TVSS surge protectors and point of use SSR / opto couplers will be at the out lets along with 12 massive symetra APC UPS dedicated to power the communication center in the basement.

Just trying to plan things out for the best / worst case scenario for the future. I have too much invested right now to let it all go up in smoke!

 

[Metal-Marc]

Is this for a commercial installation or your own equipment? When you say radio/cell, do you have a tower?

 

[Teken]

Is this for a commercial installation or your own equipment? When you say radio/cell, do you have a tower?

This is for my own use on prem. It will not be the traditional communication tower as seen by many as I am not zoned to allow such a thing in my area.

I will be however be using some liberties of installing a very nice (read tall) bird house!

If you understand my meaning this will be a dual use install . . .

The enclosure will be for a IP based PTZ IR color camera system. The actual pole will be used for the radio portion.

So that pole will have to be properly grounded etc and isolated from the rest of the electrical systems. Part of the system on that pole will be wireless so it can not be affected by a strike, only the gear on that pole can be affected (ideally) the rest comes down to proper install and fate.

 

[ishiboo]

This is for my own use on prem. It will not be the traditional communication tower as seen by many as I am not zoned to allow such a thing in my area.

I will be however be using some liberties of installing a very nice (read tall) bird house!

If you understand my meaning this will be a dual use install . . .

The enclosure will be for a IP based PTZ IR color camera system. The actual pole will be used for the radio portion.

So that pole will have to be properly grounded etc and isolated from the rest of the electrical systems. Part of the system on that pole will be wireless so it can not be affected by a strike, only the gear on that pole can be affected (ideally) the rest comes down to proper install and fate.

The pole's grounding is unrelated to the grounding of the electrical equipment, just like a roof-mount TV antenna even though the coax plugs into other grounded equipment.

There is no reason to run isolated grounds for your equipment unless you're into the vanity. It would still need to be completely separate from the tower grounds. It does not involve running a new grounding rod, just a separate wire back to the main panel. The isolated ground does not protect against lightning strikes, it's a power quality issue. Your gear will not benefit from it.

 

[Teken]

The pole's grounding is unrelated to the grounding of the electrical equipment, just like a roof-mount TV antenna even though the coax plugs into other grounded equipment.

There is no reason to run isolated grounds for your equipment unless you're into the vanity. It would still need to be completely separate from the tower grounds. It does not involve running a new grounding rod, just a separate wire back to the main panel. The isolated ground does not protect against lightning strikes, it's a power quality issue. Your gear will not benefit from it.

Sorry if I was not being clear. I was trying to explain some of the things happening at home. You're correct the grounding for the *bird house* will be separate and will not be connected to the main panel in the home.

The isolated ground is for the garage . . . I have installed three separate home run circuits which will address the isolated ground I require.

I appreciate everyone's feed back and insight.

 

[ishiboo]

Sorry if I was not being clear. I was trying to explain some of the things happening at home. You're correct the grounding for the *bird house* will be separate and will not be connected to the main panel in the home.

The isolated ground is for the garage . . . I have installed three separate home run circuits which will address the isolated ground I require.

I appreciate everyone's feed back and insight.

But you don't require an isolated ground.

 

[Teken]

But you don't require an isolated ground.

The devices I am installing into the various parts of the home do require a dedicated circuit. Since going this route will provide me with a standard isolated ground to and from the main panel this will work.

The bird house will NOT be connected to the main panel in a traditional manner, as I have come up with a plan that meets my needs while still ensuring the two areas are isolated and protected against lightning and other wiring faults.

Much thanks to all for the feed back.

 

[kaffine]

If you have copper running between the Bird House and your house then all grounds including tower grounds should be bonded.

 

[ishiboo]

The devices I am installing into the various parts of the home do require a dedicated circuit. Since going this route will provide me with a standard isolated ground to and from the main panel this will work.

The bird house will NOT be connected to the main panel in a traditional manner, as I have come up with a plan that meets my needs while still ensuring the two areas are isolated and protected against lightning and other wiring faults.

Much thanks to all for the feed back.

A dedicated circuit does not mean an isolated ground is present... two completely separate concepts. Perhaps there's a term for the ground of a "dedicated" circuit, but is not isolated as it serves two functions.

A dedicated circuit has to do with power quality, which has nothing to do with an isolated ground. (Stick something voltage-sensitive on the same circuit with a 12kBTU window AC and you'll see why dedicated circuits are called for.) Fortunately, as I said, unless you're running a hospital out of your home, you likely have zero need for an isolated ground no matter how awesome you think your stuff is.

Seems people think the more they pay for a piece of high-tech equipment, the higher tech it is and so the cleanest power is required. This is far from the truth. Most high-tech equipment could care less about its power input, as it's rectified, filtered and switch-mode regulated to exactly what it needs to be. It's the low-tech things like motors and resistive elements which care about the power quality and waveform to operate correctly.

Higher-end equipment does deal better with RF noise, one of the things the isolated ground is intended to prevent. Better shielding and balanced audio cables can make those issues nearly irrelevant as well.

As you said, what is important is proper grounding, surge protection and filtering on all the lines coming off the likely giant eyesore of a lightning rod you're installing.

 

[Greatbear]

An isolated ground installation makes the most sense in raceway or conduit installations where a number of other branches share the same common metal enclosure (at least in modern installations). Though the individual receptacles and loads are connected to ground via their own ground wiring back to the panel, these devices are also grounded via their mounting means to the common raceway. If, for whatever reason, a load in that raceway creates some current flow or EMI in its grounding means, this will tend to affect all devices in the raceway. Using isolated ground receptacles ensures that any localized noise on the raceway does not enter the receptacle's grounding means via the mountings. The ground at the receptacle will be as "pure" as what can be found at the main panel. It also means that a sturdy ground connection must be made bt the load end and panel end, as there is no "backup" found via the mounting means to the common raceway.

I have a large Wiremold raceway mounted above my one workbench that has several receptacles, including a 50amp welder socket. Among these is a single isolated ground receptacle with its own breaker that I use to plug a PC into.

 

[sberry]

Number one thing I think to protecting sensitive equipment is the surge protection and proper grounding of phone lines. My phone company installers do things their own way mainly because "I don't understand why",,,,,,,,,, so they gonna do it like they figure vs following the instructions. I have a few issues and every once in a while blow up a suppressor during storm,,, fixed the deals and only issue has been 1 lightening take out arrestor on phone co side just like its sposed to.
Thing to remember here, computers etc are grounded so if the phone line isn't proper it wants to find it thru your modem. Art 880 if I recall,, ?

 

[Teken]

Number one thing I think to protecting sensitive equipment is the surge protection and proper grounding of phone lines. My phone company installers do things their own way mainly because "I don't understand why",,,,,,,,,, so they gonna do it like they figure vs following the instructions. I have a few issues and every once in a while blow up a suppressor during storm,,, fixed the deals and only issue has been 1 lightening take out arrestor on phone co side just like its sposed to.
Thing to remember here, computers etc are grounded so if the phone line isn't proper it wants to find it thru your modem. Art 880 if I recall,, ?

Thankfully the telephone isn't one of my concerns as it is pure fiber optic from the center, NODE, and NID to my home.

The only down side in my eyes is that it is very similar to having a VOIP system on site. As the telephone in the home requires a back up battery to ensure 24/7/365 operations.

I didn't care for the small battery that they supplied me with so I replaced it with four 7.5 AH cells all wired in parallel.

The telco indicates that the small 4.5 AH cell was good for at least 72 hours or more of service time. Can't say if that is the case as the power has not been out ever for more than two hours in the last 40 years here.

I have to gather with more than 30 AH on hand that I would have at least a few months of telco power based on the specs indicated by them.

 

[mrb]

post the make / model of the fiber CPE you have. I highly doubt 4.5ah is going to give you 72 hours, and that 30ah will give you months. The common FTTH system here in the US has a 7.5ah battery and runs ~8 hours

 

[Teken]

post the make / model of the fiber CPE you have. I highly doubt 4.5ah is going to give you 72 hours, and that 30ah will give you months. The common FTTH system here in the US has a 7.5ah battery and runs ~8 hours

The Beta unit installed has the following information listed on the spec sheet. At 25 mA current consumption the 4.5 Ah cell would have easily supplied 72 hours of power for the device.

With the retrofitted 30 AH cells, along with other UPS supplying these as well I have no problem powering this device, and the others for months.

Alcatel Lucent Opitcal Network Terminal

SYSTEM TYPE
• Indoor wall mount or desktop
stand

• One GPON network interface
with 2.5 Gb/s downstream and
1.25 Gb/s upstream

• Single-mode fiber connector
(SC/APC)
SERVICE INTERFACES

• Up to four 10/100/1000 Base-T
Ethernet interface with RJ-45
jacks

• Up to two POTS via RJ-11 jacks
• Optional coaxial port (75 Ω F
connector) for RF video delivery

POWER
• Local powering with 12 V DC @ 25 mA
input
• External power supply: 110/220 V
AC input
• Optional 4.5, 7.5, 12.5 UPS for battery backup

 

[mrb]

is it a alcatel 7342?

 

[Teken]

is it a alcatel 7342?

It doesn't say what the model is, as it was a Beta unit. Just has a sticker saying Optical Network Terminal Beta Unit Rev 12.2 NOT FOR CONSUMER USE.

I tried to do a Google search for the model and picture but none of them are the exact same as mine.

Then again I have three DIN modules which are also not part of the normal set up that I have seen others in my area have. I know one of the DIN modules is microwave transceiver, the other is bandwidth modulator, the third I have no clue but it has a lot of flashy bling bling LED's which look really cool at night!

I was supposed to be done the beta test last year but no one has since called, or e-mailed since the initial set up.

So, I am still getting 40 megabytes down, and 10 megabytes up loads with no caps, or throttling.

4.7 Gb file takes aprox 30-46 seconds . . . I don't for see the good times lasting too much longer though!

 

[mrb]

do you have a multimeter that will measure DC current? I think you will find the unit draws quite a bit more than 25ma, probably 750ma to an amp. I believe the 25ma you see is the off hook loop current from each telephone line coming out of the ONT.

no way can a ONT can run on 25ma of 12v which is only .03w. Just the SOC that drives these things needs ~1W. then the laser for the fiber side, then the network stuff, the RF stuff for the television, etc, etc.