# 120V 30A or 120V/240V 50A?



## Markham85 (Nov 6, 2018)

Newbie here getting ready to have a family member electrician hook up my generator to my house using an interlock kit. If I purchase all the parts and he’s going to install for free. 

The generator I purchased, a Wen 11,000 watt dual fuel has 2 connections, 1-120V 30amp L5-30R twistlock and 1-120V/240V 50amp L14-50R connection. Correct me if I’m wrong, but the L14-50R non-locking is an RV connection? 

He suggested I use the one with higher amps, he hasn’t looked at it so I don’t know if he knows it’s not a twist lock. 

Is it ok and legal to get an RV power inlet box and cord to connect to my house and use the 120/240 50 amp outlet on my generator instead of the twist lock?


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## tabora (Sep 6, 2018)

Markham85 said:


> 240V 50amp L14-50R connection. Correct me if I’m wrong, but the L14-50R non-locking is an RV connection?


The L14-50R is not necessarily an RV connector, which is most often a 120V 30A. It is the correct 240V connector to feed into your panel through a 50A cable, a male generator in-feed connector, and a 50A 240V circuit breaker adjacent to your main breaker and controlled by the interlock for your distribution panel. An L14-50 is also commonly used for EV charging and some large 50 amp RVs. Here's a link to a typical cord and receptacle set: Conntek GISB50-025 NEMA 14-50 Power Inlet Box & Power Cord Combo


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## jkingrph (Sep 18, 2017)

That one looks like one end is a straight plug in RV type plug. My Honda EB11000 came with a 50 amp plug for 4 conductors, it's been over 15 years and cannot remember the NEMA number, but here is a link for one end.






I bought the other end, and then an inlet matching male plug to connect to my double throw switch. 

That set up in the above post looks ok, just shop around you can find it at much better prices.


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## tabora (Sep 6, 2018)

jkingrph said:


> That one looks like one end is a straight plug in RV type plug.


Most smaller RVs use the 125V 30A TT-30 Plug and Receptacle, while the big rigs with 240V 50A service use the 240V 50A L14-50. I've also seen some that are 240V 30A service with the L14-30 twistlock.

Only the latter 2 are useful for feeding a 240V main panel in a structure, depending on the output capability of the generator.


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## jkingrph (Sep 18, 2017)

tabora said:


> Most smaller RVs use the 125V 30A TT-30 Plug and Receptacle, while the big rigs with 220V 50A service use the 240V 50A L14-50. I've also seen some that are 220V 30A service with the L14-30 twistlock.
> 
> Only the latter 2 are useful for feeding a 220V main panel in a structure, depending on the output capability of the generator.



If you say so, it has been so long since I had an RV that I have forgotten all that I know about all those connectors. When I got my big Honda gen I took the plug that came with it down to the local electrical supply and had them match up a proper female end and the male input plug for me. I also picked up a couple of the little EU2000 generators last year and did some careful researching for the 30amp plug on that one so I would not order the wrong thing, Again I have slept too many times to remember all the NEMA designations

My only advice is go with the heaviest wire and plug sets that will work. I think it better to have excess capacity in the plugs and wires to give less current drop and less chance of heating. It's been well over 40 years now, but I saw a guy try to hook up a small rv with a long extension cord, using lamp cord too long and coiled up. He melted the wires and had a quick fire. We were about 70-80 feet away and had ours hooked up with I think 10 ga wire, whatever came with the small motor home at the time.


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