Running NM-B 6/2 in outdoor for 40ft in EMT conduit.

[skuk]

My garage is on other side of home to the main panel. For installing tesla wall charger. I had to run. Total of 100ft cable. I am planning to use NM-B 6/2 cable, but I had to cross the 40ft outdoor from main panel to attic. Can I use EMT conduit with rain tight coupling for the outdoor run. The run path is highlighted in red. I read mixed info on NEC Code violation about using NM-B in counduit/ damp locations

 

[skuk]

View attachment 887290

 

[rwiegand]

No, in general you can't run NM in conduit except brief runs for physical protection. (you can, in some circumstances, but it gets complicated, and complication is best avoided when talking with an inspector about a DIY project) I'd think you'd want to use UF in any potentially damp/wet location if using a multi-conductor cable, which an outdoor conduit certainly is, rainproof connectors notwithstanding-- they don't stop condensation. NM-B is not allowed in outdoor uses. Your local electrical inspector is your best source of exactly what will be allowed in your jurisdiction.

Why not use THHN in conduit? No issue then with at least that aspect of code compliance.

 

[qdeathstar]

My garage is on other side of home to the main panel. For installing tesla wall charger. I had to run. Total of 100ft cable. I am planning to use NM-B 6/2 cable, but I had to cross the 40ft outdoor from main panel to attic. Can I use EMT conduit with rain tight coupling for the outdoor run. The run path is highlighted in red. I read mixed info on NEC Code violation about using NM-B in counduit/ damp locations

Code violation

Outside run thwn

 

[qdeathstar]

300.8 and 334.12(B)(4)

 

[Sophias_dad]

In case it wasn't clear, @qdeathstar was suggesting THWN or THWN-2 in conduit, the W is for water-resistant.

 

[rwiegand]

No, in general you can't run NM in conduit except brief runs for physical protection. (you can, in some circumstances, but it gets complicated, and complication is best avoided when talking with an inspector about a DIY project) I'd think you'd want to use UF in any potentially damp/wet location if using a multi-conductor cable, which an outdoor conduit certainly is, rainproof connectors notwithstanding-- they don't stop condensation. NM-B is not allowed in outdoor uses. Your local electrical inspector is your best source of exactly what will be allowed in your jurisdiction.

Why not use THHN in conduit? No issue then with at least that aspect of code compliance.

My bad. THWN or THWN-2 (for higher temperature rating) THHN is not rated for wet locations.

 

[Art84]

I see there is a natural gas pipe, right where you want to run conduit. Clarify that you do not violate any clearances there as well, how close electrical cables can be to natural gas pipes.

 

[qdeathstar]

My bad. THWN or THWN-2 (for higher temperature rating) THHN is not rated for wet locations.

Almost all single conductor wire sold is marked thwn so not a huge deal

 

[qdeathstar]

I see there is a natural gas pipe, right where you want to run conduit. Clarify that you do not violate any clearances there as well, how close electrical cables can be to natural gas pipes.

No nec rules about that, but gas company might have a requirement.

 

[skuk]

Thanks for all the suggestions. Returning the NM-B back. I am going with below configuration

• 2nos 6AWG THWN (RED) and (GREEN)and
• 1no of 10AWG THWN Wire.
• Flex conduit all through attic and garage walls.
• EMT conduit outside home

2nos 6AWG are (RED) and (GREEN). The 10AWG is red again.
Hoping there is no NEC rule on Color of wires

Need to check on the gas line.

 

[fiehlsport]

Benefit of the THWN is you can run the wall connector at the 48A, whereas the NM-B would've restricted you to 40A.

As long as you're in conduit and not directly touching a gas line, I don't see where the gas meter would be an issue. There is no electrical junction that can be affected by gas vapor that may bleed off from the meter.

 

[qdeathstar]

Thanks for all the suggestions. Returning the NM-B back. I am going with below configuration

• 2nos 6AWG THWN (RED) and (GREEN)and
• 1no of 10AWG THWN Wire.
• Flex conduit all through attic and garage walls.
• EMT conduit outside home

2nos 6AWG are (RED) and (GREEN). The 10AWG is red again.
Hoping there is no NEC rule on Color of wires

Need to check on the gas line.

You cannot run more than 4ft of flex.

 

[fiehlsport]

You cannot run more than 4ft of flex.

Ha, I've got my wall connector hooked up with about 20ft of flex (non metallic) from the panel, anchored to each joist through my garage attic, then it transfers to solid PVC before entering the unit. I have not heard of this until now. What's the scoop on this in the code book?

Article 356 Liquidtight Flexible Nonmetallic Conduit: Type LFNC​

356.10 Uses Permitted. LFNC shall be permitted to be used in exposed or concealed locations for the following purposes:

(5) Type LFNC-B shall be permitted to be installed in lengths longer than 1.8 m (6 ft) where secured in accordance with 356.30.

356.30 Securing and Supporting. Type LFNC-B shall be securely fastened and supported in accordance with one of the following:

(1) Where installed in lengths exceeding 1.8 m (6 ft), the conduit shall be securely fastened at intervals not exceeding 900 mm (3 ft) and within 300 mm (12 in.) on each side of every outlet box, junction box, cabinet, or fitting.

 

[Sophias_dad]

2nos 6AWG are (RED) and (GREEN). The 10AWG is red again.
Hoping there is no NEC rule on Color of wires

You should go (BLACK) and (RED or another BLACK) for the 6AWG, and use a 10AWG BARE or GREEN wire for ground. Its extremely bad practice to use green for a LINE voltage, and similarly bad practice to use a red wire for GROUND!

And I'm not sure there's a rule, but it would not surprise me at all.

Wiring Color Codes - NEC Electrical Standards & 3-Phase is a source.. I'm still looking for the actual section in the code.

 

[fiehlsport]

You should go (BLACK) and (RED or another BLACK) for the 6AWG, and use a 10AWG BARE or GREEN wire for ground. Its extremely bad practice to use green for a LINE voltage, and similarly bad practice to use a red wire for GROUND!

And I'm not sure there's a rule, but it would not surprise me at all.

Wiring Color Codes - NEC Electrical Standards & 3-Phase is a source.. I'm still looking for the actual section in the code.

Good catch, running L1 or L2 on a green wire is really poor form, especially for the next guy.