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50 amp 220 over 8/3 with ground to 40 amp double breaker feeding into load center?

6K views 45 replies 6 participants last post by  stickboy1375 
#1 · (Edited)
I have bought 140 ft of 8/3 SOW w ground.

My intention is to connect a 4 prong plug into a 50a 220v box at festivals.

The line will be run from the 50a 220v to a concessions trailer using 8/3 SOW with ground.

At the trailer the 8/3 SOW with ground will run into a 2 pole 40 amp breaker.

The 40 amp 2 pole breaker will run to a 110/220v 100 amp load center.

The load center has 6 circuit breakers on two separate poles (20,15,15 and 20,15,15) that will run 12/2 to the outlets. All breakers will run 110. The two poles will not be bridged. Breaker usage: 1) 1500 w 2) 1800 w 3) 252 w 4) 515 w 5) 28 w 6) 194 w.

I am ASSuming that my breakers will not allow me to draw more than 40 amps through the incoming power line even though the festival connection is able to supply 50 amps.

Am I safe?

Diagram link ---> http://www.hstrial-gambinoconcessio.homestead.com/photo-gallery.html
 
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#2 ·
I have bought 140 ft of 8/3 SOW w ground.

My intention is to connect a 4 prong plug into a 50a 220v box at festivals.

The line will be run from the 50a 220v to a concessions trailer using 8/3 SOW with ground.

At the trailer the 8/3 SOW with ground will run into a 2 pole 40 amp breaker.

The 40 amp 2 pole breaker will run to a 110/220v 100 amp load center.

The load center has 6 circuit breakers on two separate poles (20,15,15 and 20,15,15) that will run 12/2 to the outlets. All breakers will run 110. The two poles will not be bridged. Breaker usage: 1) 1500 w 2) 1800 w 3) 252 w 4) 515 w 5) 28 w 6) 194 w.

I am ASSuming that my breakers will not allow me to draw more than 40 amps through the incoming power line even though the festival connection is able to supply 50 amps.

Am I safe?
The atmosphere you are describing inclines me to believe that the general public will be around this setup? If that is the case, no way you can do this.
 
#7 · (Edited)
The concession trailer is my own property and a certified electrician checks my wiring and the makes the final connection to the supply. If connections I have not made are unsafe no connection to power is allowed. It is not uncommon for concessionaires to do their own work then get approved by the cert electrician at the event. It is an industry standard. In fact, most of us do plumbing, construction, wiring, accounting, marketing, sales, contract negotiation, painting, signage, design, etc. The health department, building inspectors, and electricians are there to make sure nothing is unsafe. I have full confidence that no one will ever be exposed to unsafe conditions at an event. To date I have never heard of a single electric problem at an event.

I am looking for a straight forward answer as to whether my proposed set up will work or not, if you cannot provide me with the requested information then please refrain from further comments.
 
#9 · (Edited)
I am here asking people for opinions. The certified electrician at my next event will do a final approval. Unfortunately, his services are unavailable to me until then.

I have been told by my local electric supply company that this will work. However, I would never move forward without a second and perhaps third opinion. It is my experience that not every answer a person receives is accurate. Just as all certified electricians are not the same grade.
 
#10 ·
I just (quickly) looked over art 525 and the only thing that might be an issue is how you connect to power and the amps city of #8 SOW. You may be required to connect to power via a receptacle instead of hard wiring to a breaker.

8/3 SOW is only rated for 35a. Since 35a is considered a common breaker size, you couldn't fuse it at 40a.
 
#12 · (Edited)
I just (quickly) looked over art 525 and the only thing that might be an issue is how you connect to power and the amps city of #8 SOW. You may be required to connect to power via a receptacle instead of hard wiring to a breaker.

8/3 SOW is only rated for 35a. Since 35a is considered a common breaker size, you couldn't fuse it at 40a.

Its a 50amp 220 box at fairground to 8/3 grounded to my trailer where is goes to 40 amp main then individual breakers. 8/3 is rated for 40 amp. I have provided my draw which totals @35 amps. Maybe I am not understanding what you said?
 
#18 ·
8-3 flex cord would only have one hot, one neutral and a grounding conductor. How do you plan to feed the second leg of the panel?

8-4 would have two hots, a neutral and a grounding conductor.
 
#29 ·
You make a valid argument. However, I have never been able to exclude neutrals from the count and I'm not quote sure why this would be the case.
 
#32 ·
Flexible cords do not have uninsulated grounds.

As there is nothing to assure that every other circuit is turned off I feel it would be prudent to count the neutral as a CCC. In this case the reduced ampacity would apply.
 
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#38 ·
Now I see a bad plan. You would need to install an inlet on your concession stand not an outlet.

Reason being that the exposed parts on the male cord end will/could be live.
 
#41 ·
I have been thinking about this whole neutral as a CCC thing and one thing that wasn't mentioned was that in your OP you are stating the voltage as xxx/220, but I don't remember seeing of it was three phase or single phase.

It is not clear which you actually have, but a three phase service doesnt seem out of the question for this type of setting. If it is a three phase service, you will have to count the neutral as a CCC when using 8/3 W/ground SOW.
 
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