Mobile home with RV style electric source

[justjoe906]

Older mobile home with incoming power source much like an RV has. The incoming power has 50 amp cable that plugs into the pedestal with other end hardwired to indoor breaker panel.

Also have a separate cable plugged into another 50 amp outlet running to central unit that went out (lying on the ground in the picture). I have someone adding a 220 outlet in the mobile home to allow me to install a 20 amp window unit.

He's running new 10/3 wire from the 50 amp outdoor panel that will plug into the outdoor outlet. The other end he's running 10/3 wire to 20 amp breaker, then run inside the trailer to an outlet below the window.

Is the acceptable, plugging in a 20 amp cable into a 50 amp outlet? I've had several different answers with some saying no you can't but no reasons why.

Below you can see the cable running into the trailer to the breaker panel. Will be plugging in 20 amp 10/3 cable to the center plug. All will be in conduit.
The old existing cable is lying on the ground. Also is a picture of the 220 outlet below the window.

I want to do it right and not burn the trailer down. I hired an electrician and he's ran all the wires but yet to come back and wire everything up.

 

[waybomb]

The 10ga cable between the 50 amp and the 20 amp breaker is not properly protected.
Certainly not to code.
Probably unsafe.
The why of it, is because a 10ga cable can only handle 30 amps.

 

[justjoe906]

Sorry the image is of the old existing. The new cable is 10/3 and in conduit. Just to clarify the window ac unit is 220. T

 

[justjoe906]

Sorry the image of the cable on the ground is of the old existing. The new cable is 10/3 and in conduit not in use yet. Just to clarify the window ac unit is 220v 20 amp. The outlet receptacle is 50 amp. His plan is to run the 10/3 cable from the 50 amp outlet to the 20 amp breaker box then into the trailer.
So to understand are you saying the cable from the 50 amp outlet plug to the 20 amp breaker box must be 50 amp wire such as 6/3 and not 10/3, is that correct?

 

[waybomb]

Yes, if you want to/need to follow NEC. If you use THHN, you can use 8 gage.

 

[justjoe906]

They make an adapter like one of the attached. 50 amp to 20 amp. The 10 gauge is already run in conduit from the disconnect to the panel waiting to be connected. Can I use the adapter then use the 10 gauge wire with the 20 amp male plug wired on like in the picture.

All of the 10 gauge wire is in conduit running under the mobile home, however about 3 feet will need to run from the trailer to the pedestal underground. Now I'm hearing you can't run 10 gauge romex wire (orange cover) in conduit buried because it's considered a wet area. About 3 foot of it will need to be buried is liquid-tire flex conduit...
This has been a nightmare and thought the electrician I hired knew what he was doing....has been nothing but issue after issue.

He used 10/3 wire outdoors in conduit, was told you can't run orange covered romex wire in conduit outdoors and underground.
His plan was to wire the 10 gauge wire directly into the 50 amp outlet then to the 20 amp disconnect. Was told that was a no-no.
His plan was to bury the 10 gauge orange wire under-ground in a wet environment and was told that also was a no-no.

The only other option I guess would be to would be to run 6/3 generator cord that is rated for outdoor use from the pedestal to the disconnect box. However, that's 50 amp all the way to the new 20amp disconnect box and I guess a whole new set of problems.

I didn't want to do this myself because I'm not an electrician, they guy I hired is a 20 year certified electrician and I felt like he know what to do.

 

[waybomb]

The 50 amp plug is protected by a 50 amp breaker, correct? This means that the wiring from that breaker to the 20 amp must be wire rated at 50 amp. You can buy and run direct burial cable. Romex should not be used.
Emt conduit cannot be used. Imc conduit should not be used. Rigid conduit can be used. With regular THHN wire. But I prefer to run underground wires in plastibond, which is extremely expensive.

Cheapest way:
You need a 4 wire direct burial cable. It will have two black wires should be attached to the plug that connects with the black wires on the outlet. a white wire which goes to the outlet connection with the wire wire. and a green wire sound go to the round outlet.
Check that generator cable to see if it's direct burial. I am guessing it is not.

 

[justjoe906]

If I run wire such as 6/2 and plug directly into the 50 amp outlet all the way to the 20amp disconnect that the electrician installed would that be an issue? Will 20 amp breaker trip if I have an issue using 50 amp wire?

Could this be an option 50 amp reducer to 20 amp and the 10/2 UF wire as pictured below all the way to the disconnect. Looks like it can be in conduit and buried. The adapter has a 20amp built in breaker at the end. Would wire in the male outlet below to the 10/2 wire and plug into the 50amp to 20amp adapter.

At this point in time I have 50' of 10/3 Solid Romex SIMpull CU NM-B W/G wire ran in conduit that can't be buried for 3' and can't be used outdoors or in conduit apparently.

I think I need to part ways with this electrician and start over.

 

[waybomb]

If you are 100%certain you will never use that circuit for 120vac, and it will be a dedicated 240vac, then you need 3 conductors. Two hots. One ground. You need that ground for safety. I can't read the label on that coil of wire, but I am guessing it has two insulated conductors for the hots, and one bar for the ground.
But the outlet pictured is a 4 wire. I've not seen that configuration. If you go with just 3 for 240vac, you need to figure out which portions go to the hot leads of that receptacle.
As for tripping the 20 amp breaker, so long as the load is not greater than 20 amps at start up, you'll be OK.
The 50 amp protects the wire leading to the 20 amp breaker. And the 20 amp breaker protects the wire and ac unit.

 

[justjoe906]

Thanks, the adapter is 4 wires on one end the plugs into the 50 amp outlet, the other end is 3 wires that would go to the 10/2 wire.
The wire is

Southwire​

100 ft. 10/2 Gray Solid CU UF-B W/G Wire​

• #10 AWG undgerground wire for lamp posts, pumps and other loads
• UF outdoor direct burial wire is resistant to moisture and light

Southwire 100 ft. 10/2 Gray Solid CU UF-B W/G Wire 13056728 - The Home Depot

Southwire's copper UF-B cable is used in applications that include outside lamp posts, pumps and other loads. It can also be used for outbuildings such as garages and barns. UF-B feeds from a distribution

www.homedepot.com

Thanks so much helping me with this issue. I will not take up anymore of your time. ......you've been a blessing.