Converting circuit to 120v 30amp shore power

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Old 06-29-16, 09:00 AM
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Converting circuit to 120v 30amp shore power

Hello everyone. I am doing a little DIY project at my home. I need to install a dedicated 110 outlet and 30Amp 125 Shore power outlet at my dock for my boat. My home use to have central AC, and where the old AC was, is a junction box that has a pull out type dual, delayed fuse buss. The wire coming to this box, is a 10/2 fed from a dual 90AMP breaker at the panel. While learning the ropes I was a little confused as to why there was only 3 wires, I was under the understanding that 220 would run a 10/3 cable, with 4 wires inside, (2 hots, a ground and a neutral) The ground wire goes to the Ground Bus is the panel, the black wire goes to one of the breakers(of the dual) and the white wire goes to other breaker. Does this mean that there is no neutral? That the black is carrying 110, and the white is carrying 110? Because at the halfway junction box, the ground wire goes to the panel, and the white and black wire to goto the LINE screws?Anyway, I would like to reuse this extra panel as it is half way the distance I need to travel, instead of running new wire from the panel. It also has two 40AMP Delayed Fuses inside. Perhaps I could replace these with 2 15Amps?
Id liked to just continue from this box to my new 125V 30AMp receptacle.

Can I remove the dual breaker in my panel as shown (bottom left) with the single 30AMp breaker. What happens to the empty slot.

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Old 06-29-16, 11:18 AM
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There are a few confusing aspects here. It's unlikely an AC would be fed from a 90 amp two pole breaker, are you sure you traced the cable correctly? And it better not be 10 gauge wire if it is. The wire to the breaker looks much heavier, although the wire to the pull out fuse looks like it could be 10 ga. Double/triple check this.

The feed to the fuse block is 240 volts and there is no neutral.

You could repurpose the cable from the panel to the fuse block by installing a single pole 30 amp breaker, connected to black wire, and connect the white wire to the neutral bus.

I probably wouldn't bother swapping out the fuses, just use the box as a junction box and splice your new cable to the old with wire nuts. [edit] In fact, you cannot have a fuse in the neutral at all, so definitely don't use the fuses).

Let us know when we can attend the outlet christening party on your boat
 
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Old 06-29-16, 11:22 AM
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Forgot to mention, you can buy snap in blank plates to fill the extra hole in the breaker box cover (in fact, it's required by code to not leave it open).
 
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Old 06-29-16, 05:47 PM
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The heavier wires you see, are for the furnace. We live in Key Largo, where it is hot year round. This 4 bedroom 2 bath TRAILOR.... Came with a heating furnace and a fireplace. A FIREPLACE! In a trailer! And no A/C. Craziest thing ever. That was back in '87. The 10/2 black and white wires are connected behind it. We had issues with the furnace kicking on while the AC was running. Replaced the thermostat and could not figure out the problem. This was years ago. Ive since pulled the emergency disconnect bus on the furnace. Its unused. The central AC unit is also now gone, replaced with window units around the house. As the trailor got older, the duct and vents started separating and we were cooling the whole underside of the house. This is indeed the 10/2 you see at the fuse box, as since this post I have replaced an used 15Amp breaker on the bottom right with a 30Amp, and hooked the hot to it, white to neutral bus, just like you suggested but not in place of the two 90s. The A/C contractor would have done that installation many years ago. Could this improper installation been the reason for the fuse panel? I ran new 10/2 continuing from that panel to the new outlet location and just attached the line and load ground wires to the box, and capped the wires together for hot and neutral respective.

For education : Putting aside the incorrect 90amp double breaker, Why was this method used (10/2 for 240 w/ NO neutral) instead of using 10/3 with two hots and a neutral and ground? Is this common for repurposing exiting wire without replacing it or was this bad practice? What are the risks running a 240 without a neutral?
 
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Old 06-29-16, 05:54 PM
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A straight 240 volt application like A/C or a water heater does not need or use a neutral.

I don't know why I am seeing flexible cord in the panel. It should not be there.
 
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Old 06-29-16, 06:07 PM
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Yeah I noticed them right away. They appear to go to added lights in the kitchen for new cabinets my folks had installed here many years back.
 
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Old 06-29-16, 06:22 PM
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What kind of panel is that in the trailer. I see you are using Siemens breakers, but the two original 2-pole breakers at the bottom left of the panel don't look like they are Siemens breakers.

What is the 30 amp 125 volt outlet at the boat for?
 
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Old 06-29-16, 07:14 PM
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Are you saying the 10 ga wires are double tapped onto the same 90 amp breaker as the (unused) furnace connections? Yikes! That's double trouble...should not be double tapped, and WAY too big a breaker for 10 ga wire. Shut it off and leave it off until you can swap it out.
 
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Old 06-29-16, 09:05 PM
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Sure looks to be double tapped on the 2P90A breaker.

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