Generators

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ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Customer with a Gen set with nameplate of 346 amp @ 240v. Single phase. It will be mounted in an enclosed trailer used at job sights. to power their equipment that is also mounted in the trailer. Art 445.13 of the '14 NEC Indicates the conductors shall not be smaller than 115% of the nameplate current rating to the first distribution device(s). Parallel 3/0 cu in two conduits should do it but I was hoping to split that into two 200 amp CB or fused Discs to supply one large load, and a load center. I read it as I need 400 amp conductors to each disconnect. No taps. Is that correct?

The gen set is labelled as standby but will not be used in that sense.
 
ptonsparky said:
Customer with a Gen set with nameplate of 346 amp @ 240v. Single phase. It will be mounted in an enclosed trailer used at job sights. to power their equipment that is also mounted in the trailer. Art 445.13 of the '14 NEC Indicates the conductors shall not be smaller than 115% of the nameplate current rating to the first distribution device(s). Parallel 3/0 cu in two conduits should do it but I was hoping to split that into two 200 amp CB or fused Discs to supply one large load, and a load center. I read it as I need 400 amp conductors to each disconnect. No taps. Is that correct?

The gen set is labelled as standby but will not be used in that sense.
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So the generator does not have a circuit breaker? The conductors you are discussing are from the Alternator connection box to the first OCP?

I pretty sure that is what you said, I just want to verify. Generators that size often come with a CB.
 
ptonsparky said:
... I was hoping to split that into two 200 amp CB or fused Discs to supply one large load, and a load center. I read it as I need 400 amp conductors to each disconnect. No taps. Is that correct? ...
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ptonsparky said:
No CB. No fusing. Made in Brazil. More than one problem.
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I don't have any bright ideas for you.
All I have seen are a 115% feeder to a single OCP. The load side of the OCP feeding a panel or fused/CB disconnects - which would be my choice if space permitted.

I agree you can't put in two half-sized feeders each feeding a 200A panel. But that is a legal issue, not a safety or overload issue. Maybe a variance request is in order. And you will know the AHJ attitude better than I.

And, I've never seen two full sized (115% each) feeding two separate OCPs. However, (2014) 445.13 does say,
"The ampacity of the conductors from the generator terminals to the first distribution device(s) containing overcurrent protection shall not be less than 115 percent of the nameplate current rating of the generator. ..."​

It does say "device(s)". Which leads one to believe the code allows more than one "first distribution device", as in two fused disconnects. However, this puts 8 - 3/0 plus neutrals in the alternator connection box - yuck.

Like I said, no bright ideas and you already knew all of this.
 
Put a 400 amp OCPD on the generator and use the unlimited length outside tap rule for your two feeders.
 
I knew they were going to be installing the genset but they had It set and walled in when they called back with. “We’re ready.”
ADFACBE8-580E-48CC-8B28-5452C19FB234.jpg50340EFB-2C9F-490A-ABBA-380A0506FE27.jpg

As gen sets left and terminal box on right. Black and white wires to right feed a 1 ph 240 volt 10 Hp motor via starter in control cabinet in left picture. No fusing. 120v receptacle on the back of this control is fed from the bottom of that starter. No fusing. Getting parallel 3/0 out of there will be a challenge.

On a side note this 1 phase motor is rated 208-240/480 volt. First I’ve seen.

Enough problems that my AHJ is getting a call in the morning
 
JFletcher said:
:jawdrop:

I didn't realize Brazil made generators. I got to agree with Don's post.

Is there any reason to go with a single phase generator of that size, other than they got a good deal on it?
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They have one piece of equipment that draws between 100 and 175 amps with #4s running to it which looks like the max size wire that can fit in the lugs and they wanted a bigger compressor. (Insert pause to breath) The compressor came with the genset installed and ready to go.

I wasn't involved with the purchase or sizing in any way.
 
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I had my discussion with the AHJ then went back to job sight. While talking with the manager there he showed me the receptacle they used to run the trailer while it was at the shop for small projects they could do there. A 4 wire range recept with a 50 amp breaker. :?

Me:: That runs the whole system?

Him: Yes, minus the two Air conditioners, but sometimes I might have to reset it a few times.

Me: That runs off of a 50 amp breaker. Why in the world did you get a 400 amp generator?

Doing some rough addition a 40 kw might have been marginal with everything going full load. Why the higher ups decided on a 115 hasn’t been explained, nor does it matter much other than the $$$$s
 
JFletcher said:
:jawdrop:

I didn't realize Brazil made generators. I got to agree with Don's post.

Is there any reason to go with a single phase generator of that size, other than they got a good deal on it?
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Be careful when you say that condescending statement.

Brazil is third largest manufacturer of military aircraft. Generators are just a puny part of what they can achieve in terms of technology and engineering.
Don't tell that to my portfolio manager because I've got some stake on the company as part of my diversified portfolio.

EMBRAER a Brasilian corporation ( Empresa Brasileira de Aeronautica) manufactures airplanes used by big airlines like Lufthansa, Air France and American Airlines.

In addition to aircraft they also manufacture agricultural and construction machinery.

The stock symbol that is traded at NYSE is: ERJ (by its symbol you can tell it"s a blue chip corp.)

The stock price as of Dec 7, 2018 stands at $21.06 right there alongside GM, Ford, Bank of America and Pfizer.
 
myspark said:
Be careful when you say that condescending statement.

Brazil is third largest manufacturer of military aircraft. Generators are just a puny part of what they can achieve in terms of technology and engineering.
Don't tell that to my portfolio manager because I've got some stake on the company as part of my diversified portfolio.

EMBRAER a Brasilian corporation ( Empresa Brasileira de Aeronautica) manufactures airplanes used by big airlines like Lufthansa, Air France and American Airlines.

In addition to aircraft they also manufacture agricultural and construction machinery.

The stock symbol that is traded at NYSE is: ERJ (by its symbol you can tell it"s a blue chip corp.)

The stock price as of Dec 7, 2018 stands at $21.06 right there alongside GM, Ford, Bank of America and Pfizer.
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Ive heard talk that Boing is doing some joint venture stuff with Embraer. Some speculation that Bong might end up buying them.
 
kwired said:
http://manuals.chudov.com/12-Lead-Zigzag-Generator-Connection.pdf

According to document in link, about 50% of generator's three phase rating.
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Thank you. I needed confirmation. That explains the 400 amp 3ph generator with conflicting information. The model # wasn’t listed in any of the documentation.

Still glad I wasn’t involved in selecting the gen. Original had a 175 amp. This gets a 200. Not a lot for one that could see the 175 often enough.
 
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