Quick question, Wire size to a 16kw generator

[RX7Guy]

I checked out a job today and I need to wire up a 16kw Generator for the homeowner.
The run is 125' total including the wire needed outside to the generator if I go diagonal through the web joists in his basement. The breaker on the generator is 65A and the transfer switch/panel calls for a 70A breaker.

Can I run a 4-4-4-6 AL SER for the main power, or does it need to be a 2-2-2-4 AL SER?

He wanted all copper conductors and it would cost him a fortune if I had to run pipe and THHN the whole way because the run would be longer.

If I end up drunning SER would I be able to put a junction box inside, strip the SER back and run it in pipe from the J-Box to the Generator(About 12 feet)?


Also What would you guys suggest for running the four control wires?
Small FMC through the joists to the J-box?

Please excuse my ignorance, I just want to make sure I'm goign to do this right and I'm rusty on residential.
Thanks!
-Ian

 

[augie47]

I checked out a job today and I need to wire up a 16kw Generator for the homeowner.
The run is 125' total including the wire needed outside to the generator if I go diagonal through the web joists in his basement. The breaker on the generator is 65A and the transfer switch/panel calls for a 70A breaker.

Can I run a 4-4-4-6 AL SER for the main power, or does it need to be a 2-2-2-4 AL SER?

Depends on how you AHJ looks at 338.10/344.80. Most enforce the 60? rating so a 4 AL would not be adequate on a 65 or 70 amp breaker.

He wanted all copper conductors and it would cost him a fortune if I had to run pipe and THHN the whole way because the run would be longer.

Cu SER is available

If I end up drunning SER would I be able to put a junction box inside, strip the SER back and run it in pipe from the J-Box to the Generator(About 12 feet)?

If you are installing underground, No! 338.12(A)(2)

Also What would you guys suggest for running the four control wires?
Small FMC through the joists to the J-box?

Please excuse my ignorance, I just want to make sure I'm goign to do this right and I'm rusty on residential.
Thanks!
-Ian

In many jurisdictions, a OCP device is required where the generator feed enters the structure so you may want to check on that,

 

[kwired]

He wanted all copper conductors and it would cost him a fortune if I had to run pipe and THHN the whole way because the run would be longer.

I hate hooking up generators for customers that have already purchased one. You would think they would want to know how much it will cost to connect it before going ahead and purchasing it. They also buy accessories they may not need or could have purchased an alternative that would work better in their installation.

I don't even know how many people I have run into that thought we would just back feed a range or dryer receptacle to power their house from a portable generator. Explain to them why that is not a good idea and they still don't want to spend money on proper transfer equipment because it is too expensive. If I don't end up doing the work at least they were warned about possible dangers.

I have same issue with hot tubs.

 

[frogneck77]

I would run #2 SER to a jbox either inside or outside the house, then pipe to the generator-as far as the control wires, I always pull (2) 14/3 romexes to the same jbox as the ser, then splice to thhn out to the generator-I pull 6 conductors in case the generator needs 120 for a battery charger

 

[RX7Guy]

Depends on how you AHJ looks at 338.10/344.80. Most enforce the 60? rating so a 4 AL would not be adequate on a 65 or 70 amp breaker.

Cu SER is available

Thanks! I'll price out the 2-2-2-4 then. I'm not sure about how hard they enforce the 60? Temp rating, it's easier to just be in compliance.

I'll have to see about the Cu SER if the homeowner doesn't want the Auminum, I think he might not want it after he finds out about the price.

If you are installing underground, No! 338.12(A)(2)

It's all going to be above ground. We're also still on the 05' NEC here, I had to look in my 08' to find that reference. I knew that already, an ungergroudn pipe is a wet location.

In many jurisdictions, a OCP device is required where the generator feed enters the structure so you may want to check on that,

I don't think they require that where I'm at, or the OCPD in the Generator is adequate. I installed a newer model of the same generator about a year and a half ago and they didn't require an OCPD.

I hate hooking up generators for customers that have already purchased one. You would think they would want to know how much it will cost to connect it before going ahead and purchasing it. They also buy accessories they may not need or could have purchased an alternative that would work better in their installation.

I don't even know how many people I have run into that thought we would just back feed a range or dryer receptacle to power their house from a portable generator. Explain to them why that is not a good idea and they still don't want to spend money on proper transfer equipment because it is too expensive. If I don't end up doing the work at least they were warned about possible dangers.

I have same issue with hot tubs.

Tell me about it! This guy bought the generator off of his divorced neighbor who foreclosed on her house and sold everything out of it. I can only imagine what the panel looks like at the house it came from because they just cut the wires and pulled the transfer switch out.

Thank you guys for your help! I only worked in the residential/commercial field as a helper for 3 1/2 years before moving to maintenance for the local school system. I've been there for 4 1/2 years. I've gotten my Licenses in that time, but when you don't use this everyday you lose it.