A/C disconnect

[Norcal]

Seeing as how this guy is basically saying the NEC is wrong, this has gotten to troll level status.

Wheres a ban hammer when you need one?

He uses the Urban Legend Code, & the Workplace Gossip Code.

 

[brewchief]

If it worked here's one of a couple videos from Mike Holt explaining the code


Sent from my XT1254 using Tapatalk

 

[alfredeneuman]

If it worked here's one of a couple videos from Mike Holt explaining the code

CASE CLOSED Good Work brewchief!!!

 

[pattenp]

I assume Eddiek is not a reincarnate of Eddie1278 that was banned. Anyone else remember Eddie1278?

 

[wyliesdiesels]

I assume Eddiek is not a reincarnate of Eddie1278 that was banned. Anyone else remember Eddie1278?

Yes i do

 

[AntonLargiader]

From your link -

TA DA !!!

"If a 40A protection device is not capable of carrying the starting current, you can size the protection device up to 225 percent of the equipment load current rating (24A x 2.25 = 54A, next size down 50A)."

It is ALWAYS safer to up size and NEVER safer to down size electrical circuit wiring for HVAC equipment.

Just checking, you realize that describes upsizing the breaker without upsizing the conductors, right?

 

[eddieK]

I'm just saying the NEC will allow #10 copper to be protected by a 50A breaker on a HVAC condenser unit when needed even though you never see it done or would do it yourself. It seems you are stuck on determining breaker sizes base on conductor size for general purpose circuits. If I was running a 30A circuit for a resistive heating load then the breaker would be 30A because the rule is different.

I am stuck on that. Absolutely stuck on it.

Why? Who reads this forum? Think about it, do you want Joe garage to think he can wire any circuit with a smaller than standard practice?

My situation? I have never once stated I am a certified electrician, in the HVAC trade we install home run circuits and as such because this is not our #1 specialty, we err on the safer side...I would want owners to think this way too.


Locked rotor amp surges are protected well all over the states with 30 amp circuits and 30 amp breakers (typical 24 - 36k Btu systems - the most common), there is no need to up size breaker to 50, all that does in NOT protect the wire.

If you are going to under size wire, you better be a cert. sparky. If you are going to be arguing that you can do this, you need to bring in all the variables, Type wire specifically, conduit and it's material, home run un-interrupted, length of run etc etc

 

[eddieK]

Water heaters are not part of the discussion, A/C equipment is. The rules for A/C equipment allow for different wire / breaker combos then what is required for other circuits.

Yes they do - specifically better protected, not installed without wire protection.

 

[eddieK]

Just checking, you realize that describes upsizing the breaker without upsizing the conductors, right?

I do - and I've never noticed an electrician actually wiring a system this way...Why? Because it requires perfection. No room for error, no room for later operator intrusion.

The funniest part of all this is the argument to cut costs instead of erring on the side of safety.

All day, every day a system wired with correct wire size for corresponding breaker is safer than a system wired with a wire two sizes smaller than recommended.

https://i.pinimg.com/originals/d2/3f/47/d23f47fe7103ce6ab91a5c50a87c8fbd.jpg

 

[kaffine]

I am stuck on that. Absolutely stuck on it.

Why? Who reads this forum? Think about it, do you want Joe garage to think he can wire any circuit with a smaller than standard practice?

My situation? I have never once stated I am a certified electrician, in the HVAC trade we install home run circuits and as such because this is not our #1 specialty, we err on the safer side...I would want owners to think this way too.


Locked rotor amp surges are protected well all over the states with 30 amp circuits and 30 amp breakers (typical 24 - 36k Btu systems - the most common), there is no need to up size breaker to 50, all that does in NOT protect the wire.

If you are going to under size wire, you better be a cert. sparky. If you are going to be arguing that you can do this, you need to bring in all the variables, Type wire specifically, conduit and it's material, home run un-interrupted, length of run etc etc

And the electricians have been specific about the conditions that are allowed to use different size wire and breaker ratings. Who is reading the forum doesn't change what the code says.

 

[kaffine]

The problem is you were not there. I was. The failure at the bus bar was because the compressor failed, common and run winding shorted.

I am in line completely with what the manufacturers authorize.

It is not safer to under size wiring. The only examples I have been shown is for motors...A condensing unit contains a motor and a compressor, when compressors have liquid refrigerant introduced to them amperage and the associated heat ramp up rapidly, that is why it is important to properly size the wiring.

I not only follow the code I exceed the recommendations.

You can use larger breakers (max over current protection) BUT if you do, you must size the wire accordingly or that breaker is not protecting the wire.

Why did the bus bar fail? It is rated for way more than the branch circuit breaker. The circuit breaker would trip long before there was enough current going through the bus stab to melt it from over current.

 

[eddieK]

And the electricians have been specific about the conditions that are allowed to use different size wire and breaker ratings. Who is reading the forum doesn't change what the code says.

I am not disputing the code, I'm advocating holding to a higher standard on purpose which just happens to be industry practice across the board... There were years where code did not require secondary drain pans or secondary safety switches...but smart and conscientious tradesmen still installed them.

On a forum like this we have all ready had a few people mention they know nothing about electrical...How about considering what is safer, verses what is cheaper?

This is like arguing that secondary switches and drain pans are not code (when it wasn't), hence it is better to not install.

 

[eddieK]

Why did the bus bar fail? It is rated for way more than the branch circuit breaker. The circuit breaker would trip long before there was enough current going through the bus stab to melt it from over current.

Excessive amperage. That is the entire point, enough excess amperage and heat to melt the breaker and the bus bars...all breakers in a new service panel because the bus bars sustained over extended over amperage.

The point is the wiring in the circuits sustained no damage because they could handle the excessive heat/amps ...appropriately wired. Had there been a #10 copper conducter that wire would have failed and possibly caused a fire.

 

[kaffine]

Excessive amperage. That is the entire point, enough excess amperage and heat to melt the breaker and the bus bars...all breakers in a new service panel because the bus bars sustained over extended over amperage.

The point is the wiring in the circuits sustained no damage because they could handle the excessive heat/amps ...appropriately wired. Had there been a #10 copper conducter that wire would have failed and possibly caused a fire.

My point is that the bus stab is rated way higher than that wire is. If there was enough current to damage the bus then the wire would have melted as well. It was not over current that damaged the bus bar.

 

[wyliesdiesels]

Since were back on the topic of melted buss bars, its clear that EddieK also lacks a basic understanding of high resistant connections and the high heat resulting from those...

 

[alfredeneuman]

Read Note "a" of Eddie's table.
60 degree C is used for #1 and smaller. It must very old to be based on TW wire.
All in normal usage today are rated 75 degree or higher (except NM).

For instance they consider #2 the smallest size for 100 amps, but #3 can be used and is perfectly acceptable.
I recommend you consult your CODE book before you put your foot in your mouth yet again.

 

[wyliesdiesels]

Excessive amperage. That is the entire point, enough excess amperage and heat to melt the breaker and the bus bars...all breakers in a new service panel because the bus bars sustained over extended over amperage.

The point is the wiring in the circuits sustained no damage because they could handle the excessive heat/amps ...appropriately wired. Had there been a #10 copper conducter that wire would have failed and possibly caused a fire.

Wrong again.

When a bus stab is rated for 100a and a 20a breaker is melted on that stab, its logically obvious(well i guess not for some ) that high amperage is NOT the cause of the failure.

The cause of the failure is always a high resistant connection.

 

[eddieK]

My point is that the bus stab is rated way higher than that wire is. If there was enough current to damage the bus then the wire would have melted as well. It was not over current that damaged the bus bar.

Having not been on site...your opinion is noted. Meanwhile the blocked evap and condenser coils caused the over amperage not a connection overheating. The compressor did fail and the wire did not.

 

[eddieK]

Since were back on the topic of melted buss bars, its clear that EddieK also lacks a basic understanding of high resistant connections and the high heat resulting from those...

Of course you all must ignore the evap coil and condenser coil blockage causing the slugging to the compressor and the over amperage...it was the breaker that got hot in the direct short and the connection of the breaker to the bus bar that melted. In fact the entire service had to be replaced because more damage was discovered at other parts of the bus bars (both).

Meanwhile, with all of this over amperage the #6 wire did not over heat...how do you think #10 would have faired?

 

[eddieK]

Wrong again.

When a bus stab is rated for 100a and a 20a breaker is melted on that stab, its logically obvious(well i guess not for some ) that high amperage is NOT the cause of the failure.

The cause of the failure is always a high resistant connection.

The weakest link is where the failure happens...the cause is not at that point. In fact in this situation the cause was the compressors direct short. The wire did not fail because it was not #10, it was #6. Because this outdoor unit was located so close to the panel, it did not have a fused disconnect.

That high resistant connection was inside the unit compressor (direct short) cause - blocked indoor coil (evap) and clogged outdoor coil (condenser).

 

[eddieK]

Read Note "a" of Eddie's table.
60 degree C is used for #1 and smaller. It must very old to be based on TW wire.
All in normal usage today are rated 75 degree or higher (except NM).

For instance they consider #2 the smallest size for 100 amps, but #3 can be used and is perfectly acceptable.
I recommend you consult your CODE book before you put your foot in your mouth yet again.

Funny how you are still advocating cost (being cheap) over safety. #6 wire provides better protection from over current than #10 all day, every day. This is precisely why it is standard for the HVAC trade to follow the rule - #6 - 50 amp...Not #10 which is not protected by a 50 amp breaker. The breakers purpose is to protect the wire it serves. That is also in the code book.

I guess if I ever choose to not concern myself with my clients best long term interests concerning safety, I can just consult the code to save myself a few bucks. Funny thing about real life, following code does not guarantee against future damages and lawsuits...maximum wire does eliminate one factor that could come back and bite though.


Link - https://www.schneider-electric.us/d...dards/0202-iaei-news-overcurrent-prot-nec.pdf

Current Rating
OCPDs are intended to protect against excessive temperatures
in conductors or their insulation. It is essential
to match the current rating of the OCPD to the conductor
size. The current flowing through the conductor,
which has a resistance, generates heat; reducing
the conductor size from those found in the appropriate
column in NEC Table 310-16 will place the conductor
at risk of thermal damage.
Branch and Feeder Circuits.

 

[Norcal]

You still don't get it, the minimum circuit amperes already have the 125% built in, the conductors are compliant with the NEC, and the circuit breaker is just providing short circuit protection as allowed and tested. If your going to do electrical work, the code book is a required tool & if your not consulting it the work is not being done right.

 

[wyliesdiesels]

This thread is beyond absured now.

PM has been sent to an admin.

 

[NUTTSGT]

I assume Eddiek is not a reincarnate of Eddie1278 that was banned. Anyone else remember Eddie1278?

This is the first thing I thought of. I checked and unless I missed something, no it's not.

This thread is beyond absured now.

PM has been sent to an admin.

This thread is done.