# generator transfer switch & arc fault/gfci breakers



## teamo (Sep 7, 2008)

Wiring a Reliance Protrans II generator transfer switch to my main electrical panel. I am planning to use several circuits that are arc fault breaker protected and at least one gfci breaker. I know that I will lose the arc fault/gfci protection when I switch over to the generator circuits but I was wondering if the neutral connection would be interrupted. The arc fault and gfci breakers have a neutral connection from the breaker to the neutral bus on the line side and a neutral connection on the breaker for the load going out to the branch circuit(s). The generator transfer switch wires the neutral coming from the generator directly to the neutral bus of the main panel. When I switch over to generator power will I lose the neutral connection to the branch circuits that are wired through the arc fault/gfci breakers?


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## dmxtothemax (Oct 26, 2010)

Why do you think you will 
lose your gfci protection when
Using your geeny ?


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## teamo (Sep 7, 2008)

I will lose the gfci and arc fault protection because the individual branch circuit hot wires will be getting their power from the generator current and not from the utility current that comes into the main panel. I am referring to gfci and arc fault breakers installed in the main panel not the individual gfci receptacles in the kitchen or bathrooms.


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## WhatRnsdownhill (Jan 13, 2016)

that shouldnt make a difference unless you are bypassing the breakers, ground and neutral should be common between the generator and utility, so the breakers will still sense a problem and shut off...


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## teamo (Sep 7, 2008)

The transfer switch does bypass the breakers. The hot wire is removed from the breaker and is connected to the transfer switch. The transfer switch is then wired into the breaker. There are two pole switches with an off position in the middle on the transfer switch for individual circuits. Down is line (normal) the middle position is off, and the up position is for generator. See figure 4 on page #5 below.

http://www.steadypower.com/documents/ProTran2InstallationOperatingInstructions.pdf


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## WhatRnsdownhill (Jan 13, 2016)

then you will need to install gfci and arc fault breakers in the generator side to power and protect those circuits..when I say bypass the breakers, I mean does the generator have its own sub panel with separate breakers?


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## teamo (Sep 7, 2008)

The transfer switch does have it's own breakers but I don't think it is possible to replace the breakers with gfci's or arc faults because the neutral from the generator goes directly to the neutral bus in the main panel. I would have to be able to switch the neutrals of the branch circuits between generator power and utility power.


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## WhatRnsdownhill (Jan 13, 2016)

it should be able to be done,to keep the protection to the circuits that need it. I would have a qualified electrician look at the work to make sure noone gets electrocuted during the time the generator is running..


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## WhatRnsdownhill (Jan 13, 2016)

if the generator is large enough have a transfer switch just switch over the main lines coming into the house panel box so you use all the original breakers in the house panel..


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## teamo (Sep 7, 2008)

The generator is only 7500 running watts so that is why I went with the transfer switch instead of the main breaker interlock kit. I probably could have gone with a smaller transfer switch panel but with 10 circuits it leaves me some options for switching between circuits. The circuit in question with the gfci breaker is for the bathroom lights. Normally the bathroom lights don't require gfci protection but I put it on there because I have a recessed shower light with a cover and although it is high enough above the bath tub I wanted a little extra protection. The receptacles in the bathroom are on a separate circuit and have their own gfci receptacles.


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## AandPDan (Mar 27, 2011)

Do yourself a favor and return the Reliance transfer switch.

I have a 3000 watt generator. It's not the size it's how you manage your loads.

Get an "interlock" for your panel. Check with the panel manufacturer. They're very inexpensive and allow you to select ANY circuit in your home to power. You won't have any AFCI or GFCI breaker problems.


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## WhatRnsdownhill (Jan 13, 2016)

X2 on that idea , unless your transfer switch is automatic and you will overload the generator if your not home..


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## teamo (Sep 7, 2008)

If I had it to do over I would go with the interlock. I bought the transfer switch over a year ago. Long range plans are to do some major remodeling to the house in a few years. I think at that time I will do things different and change the set up for the generator. If the gfci is going to be a problem I'll skip that circuit for now and use some other lighting circuits.


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## mpoulton (Jul 23, 2009)

You are correct that you will lose AFCI/GFCI protection when running from the generator on circuits routed through that panel. However, it's worse: the AFCI/GFCI breakers will most likely trip instantly when utility power comes back on, causing a loss of power on those circuits when the transfer switch cuts back over to the main panel a few seconds later. The reason is that the load's neutral current is still routed from the load back through the AFCI/GFCI breaker even when running on the generator. That current will be seen by the AFCI/GFCI mechanism as an imbalance caused by a ground fault (AFCI's are sensitive to ground faults at 30mA) and trip the breaker. This will only happen when the utility power is on (to operate the breaker internals) and the load is still on the generator.

The breakers in that transfer switch panel are replaceable, but it looks like they do not make GFCI or AFCI breakers for it and it may not be listed for use with any other brand even if they might fit. Your better solution is probably to use a "real" transfer switch on the feeder of a subpanel.


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## redshift (Jan 22, 2016)

mpoulton said:


> Your better solution is probably to use a "real" transfer switch on the feeder of a subpanel.


Sorry to jump right into the middle of this ongoing thread, but I would like to discuss this as I am looking at doing the same thing but I am trying to wrap my head around how the neutral will be properly handled.

I have a completely full Square D HOM service panel so I need to add a sub anyway. While I'm doing that, I would also like to provision for a future backup generator so I figured why not just swing the branch circuits I plan to feed from the genny over to the sub and then use a transfer switch to feed it. I'm looking into the sub instead of one of those pre-built transfer panels for 4 reasons:

1) I have a full panel anyway and want to add branch ckts.
2) The house is 2015-built so roughly 75% of the loads (including several I want fed by genset) are on CAFCI branch ckts and regardless of the opinions on the efficacy of AFCI, it is code and I do want to pass inspection.
3) Cost of a 24-space SqD HOM panel is roughly 1/5 of those pre-built transfer panels from Reliance, etc.
4) I'll have parts commonality with my service panel (all my work stuff is QO, all my home stuff is HOM, just worked out that way and I like it)

Here is my question -- the transfer switches I've found appear to just be 2 2-pole breakers with a manual interlock -- they pass the neutral straight through. Wouldn't that be just the same as backfeeding a 2-pole in your panel with an interlock on the main? Is there a residential single-phase transfer switch that interrupts all 3 poles? I would really like to avoid the neutral bus being potentially energized from both sides.

Thanks for any advice -- feel free to tell me to create my own thread if I'm stomping all over this one.


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## mpoulton (Jul 23, 2009)

redshift said:


> Here is my question -- the transfer switches I've found appear to just be 2 2-pole breakers with a manual interlock -- they pass the neutral straight through. Wouldn't that be just the same as backfeeding a 2-pole in your panel with an interlock on the main? Is there a residential single-phase transfer switch that interrupts all 3 poles? I would really like to avoid the neutral bus being potentially energized from both sides.
> 
> Thanks for any advice -- feel free to tell me to create my own thread if I'm stomping all over this one.


Assuming your generator can be set up with an unbonded neutral (most fixed-in-place generators and some portables can), there is no need to switch the neutral. If the generator has a permanent neutral-ground bond inside it, then you technically need to have the neutral interrupted by the transfer switch to avoid having two neutral-ground bond points in the system.


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## redshift (Jan 22, 2016)

mpoulton said:


> Assuming your generator can be set up with an unbonded neutral (most fixed-in-place generators and some portables can), there is no need to switch the neutral. If the generator has a permanent neutral-ground bond inside it, then you technically need to have the neutral interrupted by the transfer switch to avoid having two neutral-ground bond points in the system.


So in that case, is spending ~$140 on a 2 pole MTS really any better than using a main breaker on the sub and installing a $40 interlock kit? (The only benefit I can see is eliminating the need for a main breaker in the subpanel which is redundant and I'm not sure if it is even code-compliant.)

And that doesn't really solve the issue with GFCI/AFCI breakers potentially nuisance-tripping if the utility-side neutral becomes energized, correct?

Since I don't have my generator yet and don't know what it will be and/or how easy or possible it is to unbond the neutral on it, would it be safest/best to seek out a 3-pole MTS and avoid the potential neutral issue? (I want to design and build this to allow compatibility with the largest selection of portable gensets possible because I only want to do the inside wiring once, but gensets will come and go.)


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## AandPDan (Mar 27, 2011)

redshift said:


> And that doesn't really solve the issue with GFCI/AFCI breakers potentially nuisance-tripping if the utility-side neutral becomes energized, correct?


I'm using an interlock. I've NEVER had any AFCI or GFCI breaker trip while on generator power even when testing the generator (utility power available).

Actually, I've never had an AFCI trip at all. Had them for more than 5 years now.


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## mpoulton (Jul 23, 2009)

redshift said:


> So in that case, is spending ~$140 on a 2 pole MTS really any better than using a main breaker on the sub and installing a $40 interlock kit? (The only benefit I can see is eliminating the need for a main breaker in the subpanel which is redundant and I'm not sure if it is even code-compliant.)


Correct. I would just use an interlock instead of a manual transfer switch. The real benefit of a transfer switch is in having an AUTOMATIC transfer switch. You seem to be describing an interlock installed on the subpanel rather than in the main panel. You could do it that way, but it's not typical. Usually you would not use a subpanel with an interlock. You'd just install the interlock in the main panel, and manually turn off the circuits you don't want to run on the generator.



> And that doesn't really solve the issue with GFCI/AFCI breakers potentially nuisance-tripping if the utility-side neutral becomes energized, correct?


That problem is unique to the specific type of transfer panel the original poster was using. It re-routes ONLY the hot wires for each branch circuit to be transferred, using a separate mini-transfer-switch for every circuit. If those individual circuits are fed from GFCI or AFCI breakers ahead of the transfer switches, it will trip the breaker when operated in generator mode with utility power on (which will always happen when utility power returns after the outage) because the neutral path will trick the breaker into sensing a ground fault. It's a special problem limited only to that specific configuration. No other interlock or transfer switch setup will cause that problem. To make a long story short, I've never seen it with one of these transfer panels (because I've never worked with one in person), but I did see the same problem occur for the same reason due to a wiring screw-up in a pool automation system.



> Since I don't have my generator yet and don't know what it will be and/or how easy or possible it is to unbond the neutral on it, would it be safest/best to seek out a 3-pole MTS and avoid the potential neutral issue? (I want to design and build this to allow compatibility with the largest selection of portable gensets possible because I only want to do the inside wiring once, but gensets will come and go.)


If you want to be able to use portable gensets without worrying about bonding, a 3-pole transfer switch would be ideal. Of course, loads of people are using breaker interlocks with portable generators all the time and nothing terrible happens despite the code violation of having a redundant neutral path. Here's a pretty good thread all about that question: http://www.diychatroom.com/f18/generator-interlock-kit-float-neutral-128453/


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## teamo (Sep 7, 2008)

I have most of the transfer switch wired up. I am going to avoid the gfci troubles and use alternate circuits for generator power. I have another question that came up during my research of this very interesting subject. 
My generator has an un-bonded neutral so I don't anticipate any problems with the breakers on the generator tripping. I did however, find this OSHA bulletin regarding bonding and grounding of generators.

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf

Based on the bulletin above do I need to drive a ground rod and leave a whip connected to it for connection to the generator frame when I use it through the power inlet/transfer swtich into the house wiring?


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## mpoulton (Jul 23, 2009)

teamo said:


> https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf
> 
> Based on the bulletin above do I need to drive a ground rod and leave a whip connected to it for connection to the generator frame when I use it through the power inlet/transfer swtich into the house wiring?


No. The generator is connected to your home's grounding electrode system when it is plugged into the house with a 4-wire connection. The ground rod at the generator would be redundant. Even if it weren't redundant, it would serve essentially no purpose anyway, which is a whole other issue...


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## Fence (9 mo ago)

I realize that this isn’t perfect and wouldn’t help with a arc protection, but would a GFCI outlet work correctly in this situation when the transfer to the generator thru a Reliance switch would then use a common neutral? Or would it trip once the neutral changes? Also, do generators generally work ok with GFI circuits?


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## georgemcq (Feb 19, 2018)

Fence said:


> I realize that this isn’t perfect and wouldn’t help with a arc protection, but would a GFCI outlet work correctly in this situation when the transfer to the generator thru a Reliance switch would then use a common neutral? Or would it trip once the neutral changes? Also, do generators generally work ok with GFI circuits?


You should check the dates of the posts to see what is current. You posted on a 2016 thread and the original people may be long gone.


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## Fence (9 mo ago)

Hi George - I was kinda' hoping that the OP was still watching this thread since his question and situation was exactly like mine. I'll set this up in a new post.

thank you,


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## Kdmedic (8 mo ago)

dmxtothemax said:


> Why do you think you will
> lose your gfci protection when
> Using your geeny ?


When you switch over to generator you eliminate the panel breakers.
The house load goes to center terminal of gen sw panel, . Then you select up for breaker panel power or down for Generator power (or visa versa)
Even though they are shared neutrals the afci and gfi are out of the circuit...unless receptacle mounted and unless your panel switches mains breaker only.


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## Kdmedic (8 mo ago)

teamo said:


> I have most of the transfer switch wired up. I am going to avoid the gfci troubles and use alternate circuits for generator power. I have another question that came up during my research of this very interesting subject.
> My generator has an un-bonded neutral so I don't anticipate any problems with the breakers on the generator tripping. I did however, find this OSHA bulletin regarding bonding and grounding of generators.
> 
> https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf
> ...


ALWAYS ground your generator. I use jumper cables on my 7500 to a permanent ground rod also used for my dog run and overhead electric cable on a 1/8" galv cable to my tree light which also has a ground cable and rod, to bleed static and lightning surges in the woods . If you dont you will get ghosting in your electrical system via un bled energy. It can fry led circuits.


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## Kdmedic (8 mo ago)

I speak from experience.


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## AirOp (Jun 8, 2019)

The protran transfer switch I saw can have the circuit breakers replaced.. so it may be possible to find afci/gfci breakers for it.


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## seharper (Mar 17, 2020)

That won't work unless _each individual circuit's neutral_ comes through the transfer switch, and is double-switched. I've never seen a 6/8/10 circuit transfer switch which does either one. 

Those things are throwbacks to the 1960s/1970s electrical code, and used every shortcut available _at the time_ to reduce cost, which is why they handle neutral in such a wonky way. 

To make GFCI/AFCI work, you need a "Critical Loads Subpanel" type arrangement, where each critical-load circuit has its 1 and only breaker in this critical-loads sub, and then the main panel and generator each send a feeder, wich is interlocked. 

I'm perfectly OK with such a panel having the Reliance brand and a $500 price tag, I'm not bigoted against Reliance. But if you want xFCI breakers to work, that's how you gotta do it because science.


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