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Steve G.
Steve G., Electrical Engineer
Category: Electrical
Satisfied Customers: 16853
Experience:  27 years in Electrical Engineering, designing electrical plans and specifications.
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I have a double wide trailer with the main panel outside and

Resolved Question:

I have a double wide trailer with the main panel outside and another in the house. It is 200amps going to the box outside. From there, there is a breaker for the well pump and the A/C.
What I need to do is get down to 100 amps on the outside panel, then to 30 amps. What I am doing is putting a 30 amp plug for my RV.
Can I just put a 100 amp breaker in the box then go from the 100amp to the 30amp?
Submitted: 10 months ago.
Category: Electrical
Expert:  Steve G. replied 10 months ago.
Hello there and welcome to Just Answer. My name is XXXXX XXXXX I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.

Now..just so I understand, you have a 200A breaker in a panel outside? If so, is there space for double pole breaker?

Please let me know so that we can continue.

Regards
Steve
Customer: replied 10 months ago.

yes I have 6 open slots


 

Expert:  Steve G. replied 10 months ago.
Ok, so why not put a double pole 30A breaker in that panel and take that to your RV connection box?

Or am I missing something?

Please let me know so that we can continue.

Regards
Steve
Customer: replied 10 months ago.


because 200a will blow everything in the RV it needs 115v 30a

Expert:  Steve G. replied 10 months ago.
Ok, you are getting confused between voltage and current.

A device (like your RV) draws the current that it requires and no more. You can put a 20A breaker in an 800A panel and you will draw no more than 20A. You could put a 20A breaker in a 1600A panel and it would draw no more than 20A. You get the idea?

Now, are you sure that you need 115V 30A? That is not a usual configuration. It is more likely that you need a 120/240V 30A feed.

In this case you would use a double pole 30A breaker in the panel and take two hots a neutral and a ground to your RV connection box.

Tell me, how many pins are on that RV connection plug?

Please let me know so that we can continue.

Regards
Steve
Customer: replied 10 months ago.


it has 3 so why cant I put a 100a in and then go from there to 30a

Expert:  Steve G. replied 10 months ago.
Because that is not how electrical design works. If you want to pay for a 100A breaker and wiring capable of carrying 100A, you would need to terminate that at another panel and then put a 30A breaker in there. This is all costly and unnecessary.

There is no reason why you can't put a 30A breaker in the panel you have now. Then you only have to pay for 30A worth of wiring, not 100A.

You will need a 30A single pole breaker that will fit your existing panel If the length of run is not excessive (over 50 feet) you can use #10 wiring.

Does that make sense?

Let me know. I'll be here.

Steve
Customer: replied 10 months ago.


just so I am sure.......................just put a 30a breaker in and hook up to the plug. 200a will not go through that 30a just 30a?

Expert:  Steve G. replied 10 months ago.
Exactly.

Again, you are confusing voltage and current. Current is determined by the device that is plugged in - your RV. And breakers are safety devices that limit the current. So again, if I had a 1600amp panel and used 20A breaker in it feeding a light circuit (for example), the light circuit would not draw 1600A. It would draw no more than 20A because if it did, the breaker would trip.

So, find out who makes your 200A panel and get a single pole 30A breaker for it. Take a #10 hot, neutral and #12 ground to your receptacle box and you are good. No more than 30A will flow through that circuit because of the breaker. And no more than 120V because you are using a single pole breaker.

I'll be here if you need further help with this issue. Please let me know.

Regards
Steve
Customer: replied 10 months ago.


Thank you very much Steve you were a big help

Expert:  Steve G. replied 10 months ago.
Don't mention it. If you need more help, I'll be here.

Here are the rating options. Please pick a good one so that I may be credited with helping you today.

Good luck.

Steve
Steve G., Electrical Engineer
Category: Electrical
Satisfied Customers: 16853
Experience: 27 years in Electrical Engineering, designing electrical plans and specifications.
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