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Initially, I'm going to be plugged into basic 120v from an outlet.

However, I'll be moving in a year, and want to be able to plug into 240v if available.

How to achieve this flexibility in the subpanel? I'll need two outlets obviously, but will I need to just rewire the input to the main breaker when I switch between 120v and 240v?


Also, I bought a Homeline 100A main panel. However, the main 100A breaker it came with is setup for double pole. How do I connect 120v, 8-2 to this safely? Do I just have to connect to one side only with the one hot line and leave the other side non-functional?

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    How many 240V loads will you have, or will all the loads be 120V? Will you have electric heaters you might want to dual-mode? Can you still take back the Homeline panel, I know of a different panel that will work m.u.c.h better... – Harper Sep 21 '18 at 22:59
  • Is this a Tiny House on Wheels, or will it be placed on a permanent foundation at some point? Will you want the capability to connect it to a full-sized electrical service (>=100A) in the future? – ThreePhaseEel Sep 22 '18 at 4:56
  • @harper I can't take back the Homeline panel, but am ok buying another one of that will work better. Also, I will only have 120v loads. – Ramsel Sep 23 '18 at 1:09
  • @threephaseeel this is on wheels. I'm not sure if I'll ever context it to a full 100A. Could happen if I find a permanent home for it. In that case, I can just redo the box completely then. I don't think it's worth doing that now. – Ramsel Sep 23 '18 at 1:11
  • @Ramsel -- how many spaces does your current Homeline panel have? – ThreePhaseEel Sep 23 '18 at 1:21
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Setting up the panel for a 120v 30 amp RV outlet would be my starting point. I would get a 50a 4 wire cord and wire it in the panel like normal red/black on the 2 main buss bars the white to the neutral buss and the green ground to the ground buss. Since this will be a sub from another feed the neutral and ground busses need to be isolated. Pull the green bond screw from the neutral to the case Or bonding wire out. Now wire the plug but don't use the one of the hots. Now in the panel use ether odd or even breakers the side connected in the plug. Later you will be able to change to the 50amp plug and the other side will be hot and you will have 240v available. I doubt both the hots will fit the 30 amp plug that's why I would only connect 1 at the plug, jumpering the 2 hots while on 120 could be done but is not safe in case you forget and put the 50a 240v plug on then there would be a direct short, not good. But with this method you would only need 1 cord this would save quite a few $.

  • So if I only use one of the hots then I'll only be able to use one side of the breaker box, correct? All of my breakers won't fit on just one side so I'll have to buy a bigger box. Is there any way to connect only one hot, say, to the left side, but then connect the right side breaker to that? Or better said, is there any safe way to do that? I suppose that's what you were getting at by "jumping the two hots", but is there a safe way to do that on the box and not the input wire? – Ramsel Sep 23 '18 at 1:16
  • As I mentioned you could jumper the 2 hots. If you have that many loads and will only be using 120v loads is your system going to be able to run on a 30 amp 120v supply? There are new codes being proposed for tiny houses all the time but the main electrical ones now require the standard 30 amp 120v and 50 amp 240v supplies similar to motor home and travel trailers. – Ed Beal Sep 23 '18 at 6:46

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