WWYD? Advice for transitioning wiring from 6-50 plug to UWC

[ryanpei1]

I've read a LOT of posts on hear about Universal Wall Connector (and gen 3 wall connector) installs, and can't quite find the answer that reflects my current situation.

The current situation:
Outdoor 6-50 plug on 6-2 Romex immediately outside the basement utility room (where entrance/panel is). Wire penetrates directly into back of wet-rated box. Has worked fine for a few years for occasional charging (at vacation house). Total wire run ~15'. Utility room is not finished. Easy access to walls and ceiling.

It's time to upgrade to UWC. It will need to be raised ~ 18" or so from the height of the current outlet. This means I won't have direct interior to exterior access to the utility room anymore (the new UWC would be on the wall outside my kitchen above the utility room, without easy wall access). Which means a short outdoor surface run.

I THINK my options are:
1) keep current Romex and transition to THWN in a j-box outside for the 18" run
2) replace the whole cable with something that can do and indoor to outdoor transition
3) run the current romex inside a sealed, 3/4" conduit outside for 18" despite knowing that NM-B is not supposed to be in a wet location. I have enough wire slack to do this.

There are three questions here:
1) What would you do? I promise not to take this as advice or recommendation. Just opinion.
2) What is best practice? (ie, would one, non-interrupted wire from panel to UWC be better than a junction box and wire connections? This seems like an unnecessary point of failure)
3) What is code? (I recognize that number 3 above probably won't meet this)

Any advice welcome (other than hire an electrician); trust me I've tried).

Thanks in advance.

 

[Eric33432]

I would do #1 using Polaris connectors to join the wires if you are happy with a 50 amp circuit and 40 amp charging. You could use a small 6 x 6 weather proof plastic surface mount box, and come out that with some 3/4" liquid tight flex.

If you need/want 48 amp charging, replace all the wiring to the panel with #6 THHN/THWN-2. You could run 3/4" liquid tight flex all the way to the panel.

Let us know what you do.

 

[tga]

I would do #1 using Polaris connectors to join the wires if you are happy with a 50 amp circuit and 40 amp charging. You could use a small 6 x 6 weather proof plastic surface mount box, and come out that with some 3/4" liquid tight flex.

If you need/want 48 amp charging, replace all the wiring to the panel with #6 THHN/THWN-2. You could run 3/4" liquid tight flex all the way to the panel.

Let us know what you do.

Exactly my vote. I would consider mounting the J-box inside so there's just an LB on the exterior with a short run of conduit out of it.

 

[Cosmacelf]

FYI 6 gauge NM-B is rated for 60A, 48A continuous in Massachusetts.

I would choose option 3 if you have slack, and can use wet rated conduit. The wires inside a wet rated conduit (like PVC or flex) don’t have to be wet rated themselves.

 

[ryanpei1]

Exactly my vote. I would consider mounting the J-box inside so there's just an LB on the exterior with a short run of conduit out of it.

Thanks! Can I make connections in the LB?

FYI 6 gauge NM-B is rated for 60A, 48A continuous in Massachusetts.

I would choose option 3 if you have slack, and can use wet rated conduit. The wires inside a wet rated conduit (like PVC or flex) don’t have to be wet rated themselves.

Really? Interesting.
I did not realize the ratings were different in MA (I'm assuming its actually a temperature derating difference or something?)
Nor did I know wet-rated conduit turned it into a dry location (for code I mean. I realize it will keep the wires dry). I assume this is local code, as NEC seems to make it clear this is not the case.
Alas, this is a Maine install.
Happen to know if ether of these are OK in Maine as well?

 

[Cosmacelf]

Thanks! Can I make connections in the LB?

Really? Interesting.
I did not realize the ratings were different in MA (I'm assuming its actually a temperature derating difference or something?)
Nor did I know wet-rated conduit turned it into a dry location (for code I mean. I realize it will keep the wires dry). I assume this is local code, as NEC seems to make it clear this is not the case.
Alas, this is a Maine install.
Happen to know if ether of these are OK in Maine as well?

I don’t know about Maine’s code. The only reason why NEC derates NM-B compared to THHN is for situations where you are running NM-B in hot attics in Insulation. Given you aren’t doing this, I wouldn’t have a problem running 48A on it, but that’s me.

As far as conduit in wet situations goes, how else would you run electrical outdoors if not in a wet rated conduit? I don’t understand your objection?

 

[ryanpei1]

I don’t know about Maine’s code. The only reason why NEC derates NM-B compared to THHN is for situations where you are running NM-B in hot attics in Insulation. Given you aren’t doing this, I wouldn’t have a problem running 48A on it, but that’s me.

As far as conduit in wet situations goes, how else would you run electrical outdoors if not in a wet rated conduit? I don’t understand your objection?

Thanks again. I agree. It would be undoubtedly safe, particularly in generally-cool Maine, which is clearly the most important.

I have no objections. And that may well be how I proceed. It seems NEC does object though. It says NB is not to be run in wet locations. Wet locations include anything outdoors. Which, I suppose is why wet-rated wire exists. While code is not always practical (ha!), I would prefer to do it right, hence question 3.

 

[Eric33432]

Thanks! Can I make connections in the LB?

Really? Interesting.
I did not realize the ratings were different in MA (I'm assuming its actually a temperature derating difference or something?)
Nor did I know wet-rated conduit turned it into a dry location (for code I mean. I realize it will keep the wires dry). I assume this is local code, as NEC seems to make it clear this is not the case.
Alas, this is a Maine install.
Happen to know if ether of these are OK in Maine as well?

I don't think you will have enough room in a 3/4" LB conduit body to splice #6 wire using polaris connectors.

Just install a 6 x 6 box in the basement and run either 3/4" liquid tight flex or 3/4" PVC conduit out that box to the wall connector using THHN / THWN-2 copper conductors. The ground can be #10 green.

Easy.

Cantex 6 in. x 6 in. x 4 in. Junction Box R5133710 - The Home Depot

The 6 in. x 6 in. x 4 in. Junction Box is an easily accessed surface mounted PVC box without entrance hubs. This box will hold multiple conduit connections and wire splices. The junction box is made of

www.homedepot.com

 

[Eric33432]

FYI 6 gauge NM-B is rated for 60A, 48A continuous in Massachusetts.

I would choose option 3 if you have slack, and can use wet rated conduit. The wires inside a wet rated conduit (like PVC or flex) don’t have to be wet rated themselves.

Well, there is always the code, and then there is the Real World. The link is a discussion of this by real electricians:

Romex in conduit outdoors

I realize romex is not supposed to be in conduit outside. An outside AC disconnect is fed by 10-2 romex inside 1/2” liquid tight about 4’ long. Should I correct it? I think heat build up is the main concern? Thanks

forums.mikeholt.com

You should do what you want to do. I say aways do it to code when it is just about as easy to comply with the code as it is to not comply.

 

[Cosmacelf]

Thanks again. I agree. It would be undoubtedly safe, particularly in generally-cool Maine, which is clearly the most important.

I have no objections. And that may well be how I proceed. It seems NEC does object though. It says NB is not to be run in wet locations. Wet locations include anything outdoors. Which, I suppose is why wet-rated wire exists. While code is not always practical (ha!), I would prefer to do it right, hence question 3.

While you do have wet rated cable, often that isn’t used. Often people use THHN inside wet rated PVC or metal conduit. I do agree with the other poster that I wouldn’t generally run romex inside conduit. Guess what romex cable is composed of? THHN wires. So what I would do is remove the romex outer covering from the end point all the way into the junction box and route your now continuous piece of THHN wiring into the conduit (liquid tight flex or PVC).

Btw, when stripping romex cover off the wires, don’t score the outer cover all the way with a knife, just start it with a knife and then pull with a lot of strength and technique to remove the cover.

 

[Jeff-4]

I don’t know about Maine’s code. The only reason why NEC derates NM-B compared to THHN is for situations where you are running NM-B in hot attics in Insulation. Given you aren’t doing this, I wouldn’t have a problem running 48A on it, but that’s me.

As far as conduit in wet situations goes, how else would you run electrical outdoors if not in a wet rated conduit? I don’t understand your objection?

Hi Cosmacelf! I've seen this and your other posts on NM-B 6-gauge wire being used on a 60A circuit. I have 6/2 Romex copper wires connecting a wall connector in my garage to a 50A circuit. The wire runs behind drywall and across the ceiling joists in an uninsulated attic, from one wall to the other in my garage, about 50 feet in total. In your opinion, could this wire be safely used on a 60A circuit? It would be nice to get an extra 8 amps in the charging session (since, in fact, this circuit is power shared between two wall connectors).

I live in Minnesota, and I will also try to find the code for this (do you have some tips to find it?).

 

[Cosmacelf]

Hi Cosmacelf! I've seen this and your other posts on NM-B 6-gauge wire being used on a 60A circuit. I have 6/2 Romex copper wires connecting a wall connector in my garage to a 50A circuit. The wire runs behind drywall and across the ceiling joists in an uninsulated attic, from one wall to the other in my garage, about 50 feet in total. In your opinion, could this wire be safely used on a 60A circuit? It would be nice to get an extra 8 amps in the charging session (since, in fact, this circuit is power shared between two wall connectors).

I live in Minnesota, and I will also try to find the code for this (do you have some tips to find it?).

I wouldn’t feel confident giving a recommendation in such a situation.

 

[Eric33432]

Hi Cosmacelf! I've seen this and your other posts on NM-B 6-gauge wire being used on a 60A circuit. I have 6/2 Romex copper wires connecting a wall connector in my garage to a 50A circuit. The wire runs behind drywall and across the ceiling joists in an uninsulated attic, from one wall to the other in my garage, about 50 feet in total. In your opinion, could this wire be safely used on a 60A circuit? It would be nice to get an extra 8 amps in the charging session (since, in fact, this circuit is power shared between two wall connectors).

I live in Minnesota, and I will also try to find the code for this (do you have some tips to find it?).

This thread has the answers to your question (and more) and discusses it in great detail if you are interested in why you should not use #6 NM-B for a 60 amp (48 amp charging) Tesla Wall Connector installation.

Home Wall Connector Install

We recently moved to a new house and the Main Panel had plenty of room and a fairly short run to where I wanted to put a Wall Connector. I was initially going to install a level 2 NEMA 14-50 Outlet and use my spare mobile charger, already purchased Homeline 50A GFCI breaker, and Hubbel 9450...

teslamotorsclub.com