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Gen-tran transfer switch, bonded neutral generator, disconnect generator ground?

Gen-tran transfer switch, bonded neutral generator, disconnect generator ground?

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  #1  
Old 02-01-11, 04:01 PM
RK2
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Gen-tran transfer switch, bonded neutral generator, disconnect generator ground?

So I found out too late that connecting a bonded-neutral generator to a non-neutral-switching transfer switch might be a tad dangerous due to the loop. I'm now wondering whether to get a different switch, generator, or do the following that gen-tran has on their site:
If the neutral bond cannot be removed [...] The easiest solution is to lift the ground wire coming from the generator inside the transfer switch, and secure it with a wire nut, by itself. This eliminates the loop.
Is this safe, and could this meet code? All circuits will still be grounded through the house ground rods, so I assume there is still a reference ground for GFCI outlets and the generator will still ground itself. On the other hand, this situation seems very similar to that of trying to use a three-wire connection to sub panel, which appears to violate code, perhaps except if the sub panel is in a detached structure and there are no other common metallic connections. Now what's correct/incorrect?

I'm about to give the manufacturers an earful on how their literature doesn't explain this stuff at all, but if disconnecting the generator ground on the switch side (which BTW I don't see listed as an option on other sites like Reliance's) is safe and meets code then I can live with it.


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Last edited by RK2; 02-01-11 at 04:30 PM.
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  #2  
Old 02-01-11, 06:40 PM
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What model of generator are you using? Most generators can easily be modified to work with your transfer switch by removing the netural to ground bond inside the generator. The main exception to this would be most of the inverter type generators.
 
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Old 02-01-11, 06:56 PM
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B&S Storm 5500W "Storm Responder." Customer support told me they do not recommend hooking it up to a transfer switchh, and that warranty would be voided when floating the ground. Then later in the conversation I was told "why don't you have an electrician fix the generator" ... well, because you said it voids warranty, didn't you? Didn't get far with that

But, I found the wiring diagram and it looks like neutral bonding is only at one of the 120V outlets. It looks like a very simple fix, and easy to verify too. Just wish I didn't have to.

http://bsintek.basco.com/BriggsDocum...25ecKPq79DteBc

Would still really like to know if Gen-tran's suggestion is sound or not, though.
 
  #4  
Old 02-01-11, 08:28 PM
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Originally Posted by RK2 View Post
B&S Storm 5500W "Storm Responder." Would still really like to know if Gen-tran's suggestion is sound or not, though.
Will it work? Yes. It is also prevents the generator from being properly grounded wich could be dangerous and probably invalidates the UL listing of the switch.

You are right about the bonding location. It is usually done by connecting the ground to neutral at one of the outlets on the generator. I would reccomend removing that jumper on the outlet of the generator. It wont hurt the generator and if you need any warranty work, just reinstall the jumper wire before you call B&S.
 
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Old 02-01-11, 09:09 PM
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The other way would be to install a 'neutral switching kit' into the transfer switch. Gen-Tran and Reliance both make one for their panels. I would do this only if you can't open the generator outlet without breaking a warranty seal or if the jumper is designed in such a way that it can't be removed without breaking it. Otherwise just remove the jumper (tape it to the generator somewhere so you don't lose it!).
 
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Old 02-03-11, 08:10 AM
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Yes, I saw the neutral switching kit. Two things: it only appears to have 8 neutrals and I have a 10-circuit switch (so I'd have to share one or two neutrals), and my switch allows a per-circuit switchover on the hot (and the neutral switch is an all-or-nothing) so I could accidentally create a situation where circuits are connected in a split fashion. Is the first up to code, and does the second not create a bad situation?

Also, it's a little odd that Gen-tran doesn't make this obvious on the order page or in the brochure/install manual. This info is hidden in the depths of the FAQ. So now I would have to add another $99 to a $300 panel, even though they say "Our transfer switches work with any generator." Yeah sure, if you buy this other thing we didn't tell you about at first.

But, my original question still stands: is Gen-tran's advice on disconnecting the generator ground wire in the transfer switch safe?
 
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Old 02-03-11, 08:47 AM
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And a follow-on question: is it indeed very unsafe (i.e., to the level of possibly electrocuting yourself) to have double bonded neutrals (at generator AND switch)? If so, I find it very odd that the Reliance Controls x-switch box at the local DYI store says something like "safe to use with any portable generator" ... there appear to be plenty of generators without GFCI protection, so you possibly don't even know there's a potential issue until you get zapped when touching the gen frame?
 
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Old 02-07-11, 07:09 PM
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It is my opinion that no harm is done if you connect the generator up to your transfer switch or home breaker panel without unbonding the neutral and ground at the generator although you should do such unbonding if easily accomplished.
 
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Old 02-09-11, 08:50 PM
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To the follow-up question: It is not unsafe at all to have the neutral bonded at two different points of a supply. The only risk would be if someone were to disconnect one point and mistakenly think the neutral was disconnected from the rest of the system. With a setup like this, I don't think that could be an issue.

The rule about only bonding the ground and neutral at one point is meant for branch circuits. If you tie a ground and neutral together in say, an outlet box, then the ground on that circuit will be carrying power. Meaning that you could become a current-carrying path by touching the grounded metal surface of any item plugged into that circuit. If current travels on the ground wire between the panel and the generator, it doesn't create a safety issue. Particularly if that ground is inside an insulated cable or raceway of some kind.
 
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Old 02-11-11, 09:12 PM
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It is my opinion that all the advice here is worth exactly what you paid for it. With that being said, hopefully one of the moderators will steer you in the right direction in regards to the code issues and the basic safetly problems brought up in this thread.

RK2, let us know what direction you finally decide to go, would you?
 
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Old 02-14-11, 10:48 AM
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Originally Posted by RK2 View Post
But, I found the wiring diagram and it looks like neutral bonding is only at one of the 120V outlets. It looks like a very simple fix, and easy to verify too. Just wish I didn't have to.
I would modify the generator here, and reconnect it if you ever need to send the generator back or use it independently of the transfer switch. If the generator is not hooked to the switch, then it is important to reconnect the bond so the built-in breaker will trip during a fault. If you go back-and-forth on a regular basis with the generator I would install a SPDT switch to bond the neutral in one direction and isolate it in the other so you can easily set the generator to "house panel" mode or "jobsite" mode.

I also don't think it would be a major issue to leave the generator bonded as-is. You will get some objectionable current on the ground wire in the hookup cord, however it is an insulated conductor.
 
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Old 02-22-11, 08:17 AM
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Originally Posted by Auger01 View Post
RK2, let us know what direction you finally decide to go, would you?
I will be modifying the generator to float the neutral and create a bonding plug for use in the 240V outlet (or put in a bonding switch) in case I need to use it with individual loads. Too much of a hassle to properly set up neutral switching in these small, per-circuit switching panels.
 
  #13  
Old 02-26-11, 03:31 PM
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So I just realized I may have a small complication: the service feed goes into a separate 200 AMP main breaker box and then has a feed to my main panel. It looks like the neutral in the main panel isn't bonded (which would make sense because there's a separate main breaker box?). So, unless I'm mistaken I have no choice but to go with neutral switching at the transfer panel so I don't in essence create a bond at the main panel ... yes, no?
 
  #14  
Old 08-27-11, 08:16 PM
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Turns out I have the same configuration (Reliance transfer switch and B&S Storm Responder generator. When connecting the generator load the transfer switch sparks and the generator breaker trips. I wonder if this is due to the neutral bond on the generator or a faulty transfer panel. I would include my wiring, but, have checked the setup multiple times and the generator to transfer panel is very straight forward. Any help you could provide is appreciated, getting ready for hurricane Irene.
 
  #15  
Old 10-01-11, 05:48 AM
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If you get a big spark at a switch pole and the breaker (here, on the generator) trips immediately, then you have a short circuit that is unrealted to the ground-neutral bonding.

However unfavorable ground neutral bonding can trip a GFCI breaker, although usually without visible sparks.

I would consider using a cord without a ground connection to connect up the generator as the lesser of two evils compared with any disassembly of the generator to unbond it. (E.g. disassemble the cord to unhook the green wire from the plug prong instead.)
 
  #16  
Old 10-02-11, 11:10 AM
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The main breaker in a 240v generator is not GFCI. He has a short, or is trying to transfer too large a load.
 
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