Generator Question

[JLCELEC]

I have a 2 pole 60 amp Manuel transfer switch. I am installing a 2 pole 60 amp breaker in my main panel with #6 wire ( 2 hots and a neutral plus ground) to feed the 2 pole 60 amp transfer switch. From the main lugs on the 2 pole 60 amp transfer switch I am feeding a sub panel with #6 wire ( 2 hots and a neutral plus ground) . In the sub panel I will have 8 ckt breakers that will be feeding various appliances (Watts will not exceed 7000). In the garage I will install a 30 Amp 240 volt Generator power cord inlet box that I will plug my portable gas Generator into with a 30 amp 240 volt cord. From the 30 amp inlet box I will be installing #10 wires ( 2 hots and a neutral plus ground) to the 60 amp 2 pole manual transfer switch.
My question is this - The transfer switch consists of two 2 pole 60 amp breakers that can not be in the on position at the same time, one of the 2 pole 60 amp breakers is going to have the # 6 wire from my main panel the other 2 pole 60 amp breaker is going to have the # 10 wire from the generator inlet box, can I have the #10 wire feed to the 60 amp breaker or is it a violation? I can't swap out one of the 2 pole 60 breakers with a 2 pole 30 breaker because that is how the transfer switch is built. The # 10 wire is carrying power that is being made from the generator then going to the 2 pole 60 amp breaker so the 60 amp breaker is not protecting the #10 wire it is protecting the 8 ckt breakers in the sub panel. So will there be any violations with the #10 wire on the 60 amp breaker???

 

[Dennis Alwon]

I think you have a problem. T. 210.21(B)(3) states if you have a 50 amp rating then the recep. must be 50 amps. It does not give a chart for 60 amps but I would infer that you can't do it. Even if you run #6 wire I believe you have a problem. You should be able to change that 60 amp breaker to a 30. What do you do when it goes bad-- change the transfer switch-- I hope not.

 

[SEO]

Does your generator have a circuit breaker that protects the receptacle that your are feeding the # 10 with ? If so what size is it?

 

[Dennis Alwon]

Does your generator have a circuit breaker that protects the receptacle that your are feeding the # 10 with ? If so what size is it?

Good point-- if that genny has a 30 amp breaker on it you should be okay.

 

[yucan2]

I don't see a problem so long as the upstream breaker at the generator is only 30 amps.

However, I do see a problem feeding the ATS from the existing panel off of a 2 pole 60. Why not a 2 pole 30 as that is all the generator is capable of producing. Not a code violation, just not necessary.

The line side of the 2 pole 60's in the ATS doesn't matter so long as the OCP of the originating conductors are fused appropriately.

 

[mcclary's electrical]

I don't see a problem so long as the upstream breaker at the generator is only 30 amps.

However, I do see a problem feeding the ATS from the existing panel off of a 2 pole 60. Why not a 2 pole 30 as that is all the generator is capable of producing. Not a code violation, just not necessary.

The line side of the 2 pole 60's in the ATS doesn't matter so long as the OCP of the originating conductors are fused appropriately.

I would leave the 60 from the panel inside. The feeders are big enough. Why limit yourself to the size of the generator, if your only gonna use it ince in a while. If there's a breaker on the gen at 30 amps, then the whole setup is fine. Even both 60's

 

[360Youth]

Transfer switch is sized for service or sub-panel, not the generator. As long as generator has OCP, you should be ok. 12-20kw standby units are installed all day long on 100a and 200a ATS.' (Under proper load calculations, of course.)

 

[yucan2]

Transfer switch is sized for service or sub-panel, not the generator. As long as generator has OCP, you should be ok. 12-20kw standby units are installed all day long on 100a and 200a ATS.' (Under proper load calculations, of course.)

I agree. However here is what I have seen a lot of. People, meaning homeowners (DIYers), will install a breaker in the originating panel totally in compliance with code. Fused appropriately, proper sized conductors, even grounding (in some cases :grin.

In this case a 2 pole 60. Then they hang a amp probe on a phase at a time and shout, ok turn it on! OK we're good. I'm only reading 59 amps :-?. We're done.

Now comes the power outage. Joe homeowner runs to grab portable generator, plugs it in, fires it up, hits his (or her), manual transfer switch and listens to the generator bog down under excessive load.

What happened? Piece of crap. What the .....!!!!

Happens all the time. I still say 2 pole 30.

 

[mcclary's electrical]

I agree. However here is what I have seen a lot of. People, meaning homeowners (DIYers), will install a breaker in the originating panel totally in compliance with code. Fused appropriately, proper sized conductors, even grounding (in some cases :grin.

In this case a 2 pole 60. Then they hang a amp probe on a phase at a time and shout, ok turn it on! OK we're good. I'm only reading 59 amps :-?. We're done.

Now comes the power outage. Joe homeowner runs to grab portable generator, plugs it in, fires it up, hits his (or her), manual transfer switch and listens to the generator bog down under excessive load.

What happened? Piece of crap. What the .....!!!!

Happens all the time. I still say 2 pole 30.

When he switches to the small panel, the panel inside is no longer a concern

 

[yucan2]

When he switches to the small panel, the panel inside is no longer a concern

My point exactly. A small 8 ckt. panel fed from a 2 pole 60 under normal conditions and a 2 pole 30 during an outage. Do you not see the potential and real likelihood for overloading the generator?

BTW, I'm nailed to a desk today. Thought I'd get my post count up a bit :roll:

 

[One-eyed Jack]

My point exactly. A small 8 ckt. panel fed from a 2 pole 60 under normal conditions and a 2 pole 30 during an outage. Do you not see the potential and real likelihood for overloading the generator?

BTW, I'm nailed to a desk today. Thought I'd get my post count up a bit :roll:

If the genset has a 30 amp OCP it will take care of itself with or without a 30 in the transfer panel. Can the home owner overload the gen on startup? YES!!!! That is why he needs a competent EC to do the calculations or be smart enough to do it himself. In th OP's case I think he has it covered.

 

[JLCELEC]

Thanks guys for all you're help

 

[LarryFine]

I don't see a problem so long as the upstream breaker at the generator is only 30 amps.

Agreed.

However, I do see a problem feeding the ATS from the existing panel off of a 2 pole 60.

It's not an ATS, it's a "Manuel" TS.

 

[yucan2]

Agreed.

It's not an ATS, it's a "Manuel" TS.

This happens every now and then, so I'll just get up out of my chair and "stand corrected", "TS" :roll:

BTW, "Manual", but who's counting...

 

[LarryFine]

BTW, "Manual", but who's counting...

(I know - that's why the quotes and wink. )

 

[kwired]

If a manual transfer switch you can transfer the entire main panel and select the load you wish to run. If you try to run too much you will trip the breaker on the generator.

If an automatic transfer you need to only transfer loads that the generator will be able to handle. This is because the automatic transfer may occur when nobody is there and if the generator breaker is overloaded it defeats the purpose of automatic transfer if you have no power anyhow. With manual transfer the transfer is supervised by the person making the transfer and if too much load is transfered someone is there to select less load.

I do not know the rules for a "Manuel" transfer switch

 

[yucan2]

If a manual transfer switch you can transfer the entire main panel and select the load you wish to run. If you try to run too much you will trip the breaker on the generator.

If an automatic transfer you need to only transfer loads that the generator will be able to handle. This is because the automatic transfer may occur when nobody is there and if the generator breaker is overloaded it defeats the purpose of automatic transfer if you have no power anyhow. With manual transfer the transfer is supervised by the person making the transfer and if too much load is transfered someone is there to select less load.

I do not know the rules for a "Manuel" transfer switch

Well one rule with a "Manuel" transfer switch and a portable generator is that one day you'll come home to a flooded basement, fridge full of spoiled food or a frozen house and wonder why you bought a generator at all.

 

[kwired]

Well one rule with a "Manuel" transfer switch and a portable generator is that one day you'll come home to a flooded basement, fridge full of spoiled food or a frozen house and wonder why you bought a generator at all.

If you are on vacation or away for several days automatic transfer is nice for these things. If you are really concerned about these things they can still happen with an automatic transfer, circuit breakers trip, GFCI/AFCI's trip, equipment fails, generator runs out of fuel, etc. If those things are that important then get a security system that will also monitor those items and automatically call you if an alarm.

If you are gone for the normal work day a refrigerator that is fairly full will stay cold for quite some time if it is never opened.

Same with frozen house. If doors and windows are never opened it will stay above freezing (if properly insulated) for many days in some cases. Water pipes in poorly insulated crawls spaces is my only concern here.