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Main service-40amp breaker going to AC unit 120' end of the house. Closeup of 40 amp breaker and 1/4" wire Disconnect at the AC unit Disconnect Instructions Actual disconnect Inside disconnect box

BR48L Subpanel

My house is 150' long. The main breaker box (pic 1) is at one end of the house and 2 Eaton Pullout Switches at the other end.

The pullout switches power 2 A/C evap coils (pic 3-6). The pullout switches are fed from 40amp breakers at the main (pic 2).

I replaced 1 of the pullout switches with an Eaton BR48L box which has a 220 breaker for the ac and a 220 breaker for a well pump (pic 7).

I have a shed 105' away from these breakers. I wan to run an extension cord down there for some lights and light drill and bandsaw work BEFORE I get my main service put in to feed the shed.

I purchased 250' 10/2 UF-B wire to create a long extension cord.

My plan was to remove the well breaker and put in a 110 20 amp breaker for this new run but there is no neutral bar.

How can I get a 110 outlet, or breaker to wire the 10/2 wire to?

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  • If the 250’ beyond the 150’ house or 400’ the voltage drop is almost 14% that’s just under 102 volts on 20 amp draw at start up I don’t see much more than a hair dryer working and anything more at startup will probably trip the 20 amp breaker. If you would have purchased 10-3 and gone to the panel it could have been done. – Ed Beal Jan 9 at 22:57
  • Is there an outdoor receptacle somewhere near the A/C units? – ThreePhaseEel Jan 9 at 23:10
  • @EdBeal The Shed is 100 feet from this power source Sorry I mentioned the 250 as I cut it in half. The 10/2 to the shed is 125' – Terrence Jan 10 at 1:21
  • @ThreePhaseEel Yes, there is an outdoor receptacle right next to this sub panel. The reason I did not want to use it is because I figured the wire was probably 14 or 12 and wanted to utilize that large 8 awg coming from the main. – Terrence Jan 10 at 1:23
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    @ThreePhaseEel Let's call it 3 months. I have the 10/2 in conduit laying on the ground, as this is a temporary solution. – Terrence Jan 10 at 1:34
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In that pico-panel, you have a major defect. You have the breakers incorrectly swapped. You have a 40A breaker on the thin wire and a 20A breaker on the thick wire. The thin wire is totally unprotected. Swap those breakers!

You are correct. Without a neutral, that pico-panel cannot support any 120V loads end of subject.

You cannot use UF-B as extension cord and I cannot imagine what you were thinking there. Being solid wire, it is not flexible like a cord must be. It is not designed to be flexed over and over. You need cordage such as SJOOW.

If one 10/2 UF-B is run in conduit the conduit must be 3/4" or larger. Nothing else can be in the conduit.

Honestly, I think your best bet is to run the proper and final feeder that you ultimately want from your main panel to the shed. I advise against having the power company drop you another service, because the power company has a new trick: they are charging people a "minimum provisioning charge" which, if you cancel service, becomes a "service availability fee". That is, they charge you for the fact that you could have a service drop if you wanted it. I now have 2 sites with 2 PoCo service drops each, and they charge us $60 a month per drop no kidding. They won't let us out of either one. So needless to say, if I have to haul power 1000' I'll feed off my existing service rather than order a new one.

Service size has no bearing on it; one is 240V/100A and another is 480V/1000A. Same $60.

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  • Great point on the feeder vs service thing – ThreePhaseEel Jan 10 at 3:22
  • @Harper The conduit is 3/4". Your comments about having another drop are valuable. The reason I am considering it is there is a city electric pole 20' from the shed. My main breaker is about 250' away. I am weighing the cost of running the big wire 250' from my main vs the minimum monthly cost of the new service and a short 20' run. The install cost of the 250' big wire divided by the minimum monthly fee is my expected monthly break even number. Thoughts? Thank you for all of your inputs. – Terrence Jan 10 at 5:14
  • @Harper >>You have a 40A breaker on the thin wire and a 20A breaker on the thick wire. The 20A is for the AC and is what the unit is rated for. The 40A is for the well pump and the large amps is for the initial surge upon start up. The well is only run once in a blue moon. Couple times a week in the summer and that is about it. Do you still think I have an issue here? – Terrence Jan 10 at 5:26
  • @Harper >>You cannot use UF-B as extension cord. "Extension cord" was a way of saying "not a permanent run". The UF-B is sitting in 3/4 conduit and is lying in a straight line. When I am finished with this project, it will be rolled up on a large spool, rarely getting flexed. – Terrence Jan 10 at 5:29
  • Thank you pointing out SJOOW. – Terrence Jan 10 at 5:35
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There are too many problems to go forward with your plan:

FYI Those pull out things are disconnects.

You can not use a 40 amp circuit for a 20 amp device.

Both of those circuits use the white wire for a hot so you have no neutral available

The UF would need to be buried not an extension cord

If you come up with a 120v circuit to feed that distance with #10 wire you would have a ~7% voltage drop with only a 15 amp load. Almost 9% at 20 amps.
A motor load on 120 volt because of the distance the voltage drop this will cause the current to be higher and trip the breaker because even with 10 awg copper a receptacle can not be supplied by larger than a 20 amp breaker. I am thinking 1/2 hp or larger motor will trip at this distance.

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  • thank you for your input. Yes I was concerned about running anything but lights. – Terrence Jan 10 at 1:19

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