Breaking the Neutral to Utlity Company

[Ron Poehlmann]

I have an electrician who has installed a generator (permanent installation) and an ATS in a residence. The installation is in a rural area and the rural electric co. wants the neutral broken when the generator is supplying power. I did not think this was necessary and from reading other posts it sounds like it is not. None-the-less the utility co wants it broken.

The homeowner is not willing to pay the cost of a new ATS that switches the neutral, and the electrician doesn?t want to eat the cost. So I am trying to help out and not hang myself out to dry.

I was going to have him install a definite purpose contactor to break the neutral between the meter and the neutral bar in the ATS, but as I think about it I have a few concerns.

The contactor may last 20 or 30 years before it fails, but when it does the residence will loose the neutral.

The other concern is that when switching back from generator power to utility power the contactor may not switch as fast as the ATS and there could be a short duration without a neutral.

Has anyone seen this situation and a good solution? Are my concerns well founded, or did I miss the big one?

 

[iwire]

First off definite purpose contactors are the bottom of the line when it comes to contactors.

Second the NEC does not require the neutral to be broken and there is absolutely no reason it needs to be.

Third what has the power company have to do with it?

Unless they can show in writing that their 'terms of service' require the neutral to be broken I would tell them to go pound sand.

 

[ptonsparky]

Why was the Poco consulted in the first place?

 

[ron]

Don't hang yourself out to dry. If the neutral needs to be switched, it needs to be part of the same mechanism as the phase switch for the points you made in the OP.

 

[jrannis]

I have an electrician who has installed a generator (permanent installation) and an ATS in a residence. The installation is in a rural area and the rural electric co. wants the neutral broken when the generator is supplying power. I did not think this was necessary and from reading other posts it sounds like it is not. None-the-less the utility co wants it broken.

The homeowner is not willing to pay the cost of a new ATS that switches the neutral, and the electrician doesn?t want to eat the cost. So I am trying to help out and not hang myself out to dry.

I was going to have him install a definite purpose contactor to break the neutral between the meter and the neutral bar in the ATS, but as I think about it I have a few concerns.

The contactor may last 20 or 30 years before it fails, but when it does the residence will loose the neutral.

The other concern is that when switching back from generator power to utility power the contactor may not switch as fast as the ATS and there could be a short duration without a neutral.

Has anyone seen this situation and a good solution? Are my concerns well founded, or did I miss the big one?

I think their business stops at the load side of the meter. I think you are creating more problems by opening the neutral than its worth.
Maybe go with the contactor and correct it after they leave the property

 

[bob]

Ron P
Make sure you understand the differences in the grounding of the generator when you break the neutral and when you don't.

 

[S'mise]

Don't hang yourself out to dry. If the neutral needs to be switched, it needs to be part of the same mechanism as the phase switch for the points you made in the OP.

Exactly, The contactor sounds like a bad idea to me.

Switching the neut is dependant on whether the generator is seprately derived. Refer to the generator manual. Either change the ATS and ground connections or don't touch it at all. I would be talking to the ahj, Not the poco.

 

[ohmhead]

Well if its a home service less than 1000amps your fine unless you have GFI protection on that main breaker like a commercial job i dont think so .

POWER COMPANY IS WRONG !

Only use a 4 pole when you have a GFI in system as when you dont it does not work well and you have 2 paths to a low impedance so you switch it or break it in your case you dont have to do it .

Also when you ground your service dont ground the generator again its done only once on a solid neutral ats at your service disco .

 

[Ron Poehlmann]

Exactly, The contactor sounds like a bad idea to me.

Switching the neut is dependant on whether the generator is seprately derived. Refer to the generator manual. Either change the ATS and ground connections or don't touch it at all. I would be talking to the ahj, Not the poco.

This is a rural install and the ahj is the county. The county doesn't have a real policy on this so they refer to the requirements of the poco.

I believe I am correct in saying that the generator is not a sds. There is a neutral and ground wire run with the generator power wires and the neutral is not bonded to the ground at the generator. The bonding of the neutral and ground only happens in the ATS and the GEC is terminated in the ATS. The ATS is service entrance rated and has a breaker for utility and generator power to act as a service disconnect for each. I believe it is properly labeled as well.

 

[LarryFine]

I believe I am correct in saying that the generator is not a sds.

Aye, and there's the rub. With a switched neutral, the genny would be an SDS, which is apparently the POCO's desire.

Ideally, the homeowner and the PoCo would hash this out directly, and leave the electrician out of the fray. Ideally. :roll:

Fighting the PoCo isn't easy, and is rarely successful, unless it can be "proven" that they're wrong. It's their football.

 

[LarryFine]

First off definite purpose contactors are the bottom of the line when it comes to contactors.

Semi-unrelated: Bob, why do you say that? What would you use to, say, switch appliances in an Ansul-type system (not using shunt-trip breakers)?

 

[benaround]

Semi-unrelated: Bob, why do you say that? What would you use to, say, switch appliances in an Ansul-type system (not using shunt-trip breakers)?

Larry, Not to answer for Bob, but a latching type contactor would be an upgrade. I can

just see a cheap contactor with the neutral running through electricly held coil, next to

the heavy duty contacts of the ats.

 

[iwire]

Sorry Larry I had not seen you're questions

Bob, why do you say that? What would you use to, say, switch appliances in an Ansul-type system (not using shunt-trip breakers)?

If left to me I would use a listed contactor like a NEMA design contactor.

My views come from my own observations and a number of posts like these on the forums.

LOL, the age old DP debate.

NEMA = "Find it, Fix it and Forget it!"
Overbuilt for the US auto industry to take the worst possible thing a 'Lectrician could throw at it without having to talk to the overpaid engineering staff about the application. Probably more than most people need, but cheaper in the long run if down time costs $1000 / minute and it takes 10 minutes to get an Engineer on the phone.

IEC = "You can be fine if you've got the time."
Born in Europe where everything has to be "rationalized" by a degreed Engineer. Needs to be engineered for mechanical and electrical life, voltage, current, duty cycle and operating conditions, but there are very specific charts and formulas made available in catalogs for whomever needs to do it, all based on defined IEC "utilization categories" such as AC-1 through AC-6a. Came in full force to North America in the 1980's when we started getting our asses handed to us on productivity of repetitively built machine controls that could be engineered once and built many times. Still not looked favorably on by most end users, but accepted because their buyers go for the lowest price and/or smallest package. By the way, HID ballasted lamps are under AC-5a if you want to get the proper ratings.

DP = Don't Purchase in lots of under 1000 pieces."
Intended for specific use on specific equipment for specific loads running for a specific amount of time (i.e. just long enough to last out the warranty, no more, no less) without specifically costing a penny more per hundred lot than is absolutely necessary. Every aspect needs to be looked at individually, i.e. making capacity, breaking capacity, duty cycle, environmental contamination, ambient temperature, vibration, voltage fluctuations etc. etc. etc. There are no charts to help you, the manufacturers just make their information available and the onus is on you to take all the necessary issues into consideration. Then when it's all said and done, it is only UL Recognized (UR) as augie47 said. That means that IF you are a UL panel shop, you may use them only IF you add them to your procedure and have the entire assembly, including the SCPD upstream and any other devices downstream, evaluated and engineered. The cost to the panel shop for that UL evaluation is reportedly over $2000.00 per line item now (I gave up my UL shop 13 years ago and it was only $200 then). The only reason why you can buy DP contactors individually is because they need to be available for specific replacement purposes, and even then it has to be an exact replacement or one recognized by the equipment manufacturer as a legal substitute. ANY OTHER USE OF A DP CONTACTOR IS TECHNICALLY A VIOLATION!. More and more inspectors are getting wise to this issue now that SCCR ratings are being enforceable in the new code.

And yes, you are NOT going to be able to get an SCCR rating of any kind on a stand-alone DP contactor, not even the "courtesy" 5kA for untested devices, because IT IS NOT UL LISTED IN THE FIRST PLACE! To get an SCCR rating you need to go with IEC or NEMA designed products and ask the manufacturers for a combination listing. That will usually be with fusing or THEIR OWN BRAND of circuit breaker.

 

[LarryFine]

If left to me I would use a listed contactor like a NEMA design contactor.

The reason I have used el-cheapo contactors is because the only times they'll be operated under load is when the system is tested or when there's a fire; maybe five to ten times in its lifetime.

And the cost, of course.

 

[benaround]

The reason I have used el-cheapo contactors is because the only times they'll be operated under load is when the system is tested or when there's a fire; maybe five to ten times in its lifetime.

QUOTE]

Larry, I don't like to wire the ansul system n.c., mostly because someone down the line

could open the control power circuit and disable it without knowing it. Along comes a fire

and nothing shuts down, next thing you know your phone is ringing.

 

[LarryFine]

Larry, I don't like to wire the ansul system n.c., . . .

Nor do I. The contactor is energized during appliance use. If the coil opens or otherwise loses power, the appliance will not turn on.

I agree that failure into the safer condition is preferable. NO contactors are cheaper anyway.