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Author Topic: sub panel....  (Read 404 times)


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sub panel....
« on: September 14, 2017, 10:31:04 AM »
  It seems confusing to me, because I have never had a 30 amp sub panel to work with. So, please bare with me, I will make it as short as possible. This spring a bought a used camper for 600 bucks. It was a real junker, but, I wanted that frame, it was worth it. The small panel box only had 5 places for breakers, It is old, put the electrician OKed' it. Because it is so hold, I can't get anymore breakers. It is wired funny as well. I pulled it all out for the rebuild. I should have taken a photo first. I need a 30 amp breaker to run the in-line water heater. I do have a 40 amp breaker that would work, maybe? I want to hook the cable line in to the 40 amp breaker, and use the 30 amp for hot water.
It is a 30 amp single pole breaker. Any ideas? The cable coming in has 2 different heads...does that say how much is coming in at the camp site? Should it be 50 amp coming in, if so, how do I change that? Any advice would be great. Thanks again guys...Donny ( I hope that's a clear message)


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Re: sub panel....
« Reply #1 on: September 14, 2017, 11:06:45 AM »
It's not an old Federal Pacific brand is it?  If it is, drop whatever you are doing and remove it from service.  They are very dangerous and must be replaced.
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Re: sub panel....
« Reply #2 on: September 14, 2017, 11:29:17 AM »
If the box came from an old camper, the whole thing may only be rated for 30 amps. There should be a sticker or label stating the box and bus rating.
Exactly what are you doing with the panel? Are you using it power up the camper again? If so, you don't need 30 amps to run any RV water heater. A 20 amp circuit will be plenty, and most run off of a  15 amp circuit. Or are you wiring to a household water heater?
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John From Detroit

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Re: sub panel....
« Reply #3 on: September 14, 2017, 05:49:55 PM »
First amps and poles have nothing to do with each other any size breaker can be single or double (or triple) pole depending on the load. ANY SIZE.

A Sub Panel is wired the same as a main panel with the following changes.

1: Neutran and ground are NOT bonded together as they are on the main (Service Entrance) panel.
2: YOu may or may not have a 'Main" breaker, it is optional.

If your RF is 30 amps. it likely does not have enough electricity for an "inline" (Demand type) Water heater.. That would take close to 30 amps at 240 volts to be effective and 30 amp RV's don't have 240 volts.  Only 50s and then only on 50 amp sites.
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Re: sub panel....
« Reply #4 on: September 14, 2017, 08:54:05 PM »
Throw the old, obsolete subpanel away - a new one will be easier to work with and they don't cost much. You want a panel with either a 30A or 50A main breaker and whatever number of branch circuit breaker slots you will need.

If your water heater alone needs a 30A breaker, then obviously a 30A external power source is not going to be adequate. That means you want 50A panel unless this rebuilt trailer will never go to campgrounds and will be hardwired to some other power source. Campground standard power is either 15A/120v, 30A/120v, or 50A/240v.

Your questions indicate you have no knowledge of 120/240v power systems and wiring, so I suggest you get an electrician to help, if not to do the whole job. That way nobody gets electrocuted and the rig doesn't go up in flames.
Gary Brinck
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Home: Ocala National Forest, FL


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Re: sub panel....
« Reply #5 on: September 17, 2017, 07:51:48 PM »
I agree with Gary 100%, someone asking these types of questions needs to get a professional to do the job. As for the Federal Pacific breakers, there are retrofits available but 1 breaker will cost more than a whole new Challenger/Cutler Hammer panel with all the breakers. I am an electrical contractor and when a homeowner calls asking what size wire to pull for a certain size service I tell them to get the National Electrical Code book and figure it out, it's all in the book how to calculate voltage drop over a length and wire size for service entrances, etc.
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