Installing Level 2 at Home (SOOW vs. NM-B) Which one?

[wwhitney]

I'm a bit dense today. Am I reading you correctly that a hard-wired EVSE with a short cord and with GFCI built-in does not require a GFCI breaker according to 2020 NEC ?

If it's hardwired, then there won't be a cord. Otherwise, yes.

As to the two requirements, I'm saying that the new-to-2020 requirement for GFCI protection of any receptacle used for a cord-and-plug connected EVSE did not change the much-older requirement that every EVSE incorporate GFCI-like protection, along with limits on cord length relative to the location of that GFCI-like protection. Both requirements are in force under the 2020 NEC, or the 2017 NEC with TIA.

Cheers, Wayne

 

[SageBrush]

As to the two requirements, I'm saying that the new-to-2020 requirement for GFCI protection of any receptacle used for a cord-and-plug connected EVSE did not change the much-older requirement that every EVSE incorporate GFCI-like protection, along with limits on cord length relative to the location of that GFCI-like protection. Both requirements are in force under the 2020 NEC, or the 2017 NEC with TIA.

Cheers, Wayne

OK... I think I am following. Rewritten for the feeble-minded like me ... please correct if needed:

NEC 2017 required GFCI like performance in all pluggable EVSE, along with a cord under 12"

NEC 2020 still has the NEC 2017 requirement, and in addition requires a GFCI breaker.

 

[wwhitney]

NEC 2008 and newer (I didn't check earlier than that) require GFCI like performance in all EVSEs, with a maximum unprotected cord length of 12" (if there is a cord).

NEC 2020 (and NEC 2017 with TIA) in addition requires GFCI protection for any receptacle used for plug-connected EVSEs, which protection is typically a GFCI breaker. No requirement for hardwired EVSEs.

Cheers, Wayne

 

[LeftieBiker]

If it's hardwired, then there won't be a cord.

Quite a few EVSEs come with a short cord that can either be wired to a plug, or used to hardwire the EVSE. I think that most home-installed EVSEs, and quite a few electrician-installed ones, use this setup. Sagebrush was asking if that short cord (or cable, if you prefer) between the EVSE and the junction box affects the waiving of the GFCI rule for hardwired installations. I hope not. As for there being no conflict with two GFCIs in series, we've seen issues when a portable EVSE with built in GFCI is plugged into a GFCI outlet. Maybe this isn't a problem with hardwired installations...

 

[SageBrush]

If it's hardwired, then there won't be a cord.

Quite a few EVSEs come with a short cord that can either be wired to a plug, or used to hardwire the EVSE. I think that most home-installed EVSEs, and quite a few electrician-installed ones, use this setup. Sagebrush was asking if that short cord (or cable, if you prefer) between the EVSE and the junction box affects the waiving of the GFCI rule for hardwired installations. I hope not. As for there being no conflict with two GFCIs in series, we've seen issues when a portable EVSE with built in GFCI is plugged into a GFCI outlet. Maybe this isn't a problem with hardwired installations...

I eventually took Wayne's use of 'cord' to mean something that ends in a plug. Perhaps the stub that is directly connected to the J-box is called a pig-tail ?

 

[pr0lab]

Make sense. thanks.

What is your opinion on 2-2-2-4 Gray Stranded AL SER Cable? it's bout half the cost of the copper cable but of course it's overall thicker given it's AL.

Thank you. To summarize, I am thinking of actually putting a 50 amp breaker and doing the 50 amp wiring so either #8 cable with rubber conduit or using the UF cable without conduit to the 14-50 outdoor receptacle. which would you recommend? which is the easier to work with? I like not having to deal with conduit in the UF 6/3 cable but it's very think too.

See my advice about hiring a professional. Or at least get a knowledgeable friend to help. Do you have a torque screwdriver?

A cable is an assembly of multiple wires. With conduit, you'd typically use individual wires.

Conduit is not made of rubber.

6/3 UF and a 50 amp GFCI double pole breaker would allow you to install an outdoor 14-50 receptacle without any need for a changeover in wiring method or splice. Or 8/3 UF and a 40 amp GFCI, with the optional but good idea label.

Cheers, Wayne

 

[wwhitney]

If it's hardwired, then there won't be a cord.

Quite a few EVSEs come with a short cord that can either be wired to a plug, or used to hardwire the EVSE.

The ones I have seen, for hardwiring you remove the plug and the cord, and bring your building wiring directly into the wiring compartment of the EVSE, where the cord previously terminated. I don't believe it would be compliant to use a cord without a plug as a form of hardwiring. You could swap the cord out for a short whip of LFNC or the like, but that just adds another junction box and splice.

Note that cord here has a specific meaning, it's one of the flexible materials listed in Article 400 of the NEC, Building wire would be one of the wiring methods discussed in Chapter 3 of the NEC.

Cheers, Wayne

 

[wwhitney]

What is your opinion on 2-2-2-4 Gray Stranded AL SER Cable? it's bout half the cost of the copper cable but of course it's overall thicker given it's AL.

My opinion is that SER cable is a fine choice for indoor/outdoor (but not below ground) cable. 6-6-6-X SER would be sufficient for a 14-50 receptacle, since SER is a 75C wiring method. Note that if your EVSE specifies "copper wiring only" then you would need a junction box to switch over to copper for hardwiring. For a receptacle, make sure it is listed as Cu/Al.

Cheers, Wayne

 

[Flyct]

Thank you everyone for your help!

I am looking at the sizing and wondering is there a reason why #8 THHN wire https://www.homedepot.com/p/Southwi...anded-CU-SIMpull-THHN-Wire-20490999/204632886 would not work? it's rated for 55 amps https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/ looking at the ampacity chart

Yes 8 AWG THWN in conduit is fine for 50 amps assuming the wire run isn't too long. That Home Depot 8 AWG or larger wire is THHN/THWN rated. THWN is required for outdoor use. That’s how my shed was wired for my Nissan 240v EVSE.

I initially installed a 40 amp breaker but I have since replaced the breaker with a 50 amp breaker since it’s now used to occasionally run my 50:amp RV or my friend’s Tesla EVSE that draws more current. It’s only a 6 foot run from the sub panel to the 14-50R outlet. 8 AWG is easier to work with vs 6 AWG.

 

[LeftieBiker]

The ones I have seen, for hardwiring you remove the plug and the cord, and bring your building wiring directly into the wiring compartment of the EVSE, where the cord previously terminated. I don't believe it would be compliant to use a cord without a plug as a form of hardwiring. You could swap the cord out for a short whip of LFNC or the like, but that just adds another junction box and splice.

Thinking more about it, at least some of the EVSEs that come with a short...'wire bundle' actually use BX armored cable with the wires inside. That's how the Clipper Creek EVSE I bought years ago (and have yet to install) came. I still think I've seen some with just a standard heavy duty power cord that were connected to a box, but now I'm not sure about just how common that is.

 

[pr0lab]

Thank you everyone for your help!

I am looking at the sizing and wondering is there a reason why #8 THHN wire https://www.homedepot.com/p/Southwi...anded-CU-SIMpull-THHN-Wire-20490999/204632886 would not work? it's rated for 55 amps https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/ looking at the ampacity chart

Yes 8 AWG THWN in conduit is fine for 50 amps assuming the wire run isn't too long. That Home Depot 8 AWG or larger wire is THHN/THWN rated. THWN is required for outdoor use. That’s how my shed was wired for my Nissan 240v EVSE.

I initially installed a 40 amp breaker but I have since replaced the breaker with a 50 amp breaker since it’s now used to occasionally run my 50:amp RV or my friend’s Tesla EVSE that draws more current. It’s only a 6 foot run from the sub panel to the 14-50R outlet. 8 AWG is easier to work with vs 6 AWG.

Thank you. My run is 50 ft. no sure what you would refer to as too, over what distance? Also, what size conduit did you use, if you used 4 wires?

 

[SageBrush]

https://wesbellwireandcable.com/blog/thhn-thwn-and-thw-acronym-meanings/

THHN, THWN and THW are all types of single-conductor electrical wire used in homes and buildings to deliver power. Previously, each acronym was a completely different wire with different approvals. Each type was specific to an application and cost as such. THHN wire prices, for instance, were higher than those for non-nylon wires. However, nowadays, there is a universal THHN-2 wire that covers all approvals from all variations of THHN, THWN and THW.

 

[Flyct]

Thank you everyone for your help!

I am looking at the sizing and wondering is there a reason why #8 THHN wire https://www.homedepot.com/p/Southwi...anded-CU-SIMpull-THHN-Wire-20490999/204632886 would not work? it's rated for 55 amps https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/ looking at the ampacity chart

Yes 8 AWG THWN in conduit is fine for 50 amps assuming the wire run isn't too long. That Home Depot 8 AWG or larger wire is THHN/THWN rated. THWN is required for outdoor use. That’s how my shed was wired for my Nissan 240v EVSE.

I initially installed a 40 amp breaker but I have since replaced the breaker with a 50 amp breaker since it’s now used to occasionally run my 50:amp RV or my friend’s Tesla EVSE that draws more current. It’s only a 6 foot run from the sub panel to the 14-50R outlet. 8 AWG is easier to work with vs 6 AWG.

Thank you. My run is 50 ft. no sure what you would refer to as too, over what distance? Also, what size conduit did you use, if you used 4 wires?

Yes, 4 wires of #8 THWN in 3/4” PVC Conduit for 50 amp 240 volts outlet. . We did exactly this at a friend’s vacant lot to run a 50 amp RV outlet. We buried 75 feet of 3/4” PVC Conduit from the panel to the RV post and put in a 50 amp RV box. .

You should be fine running 75 feet of 8 AWG THWN in 3/4” SCHEDULE 40 PVC conduit. According to table you can use up to 5 #8 wires in 3/4” SCH 40 PVC Conduit. https://www.elliottelectric.com/staticpages/electricalreferences/ElectricalTables/Conduit_Fill_Table_PVC.aspx

The rule of thumb is less than 3% voltage drop. A 75 foot run of 8 AWG THWN drawing 50 amps would be well under the 3%. 50 feet from source to outlet and another 25 feet to account for bends etc.

https://www.calculator.net/voltage-drop-calculator.html?necmaterial=copper&necwiresize=3&necconduit=pvc&necpf=0.85&material=copper&wiresize=0.4066&resistance=1.2&resistanceunit=okm&voltage=240&phase=ac&noofconductor=2&distance=75&distanceunit=feet&amperes=50&x=52&y=13&ctype=nec

Disclaimer: I am not a liscenced electrician but I’ve pulled homeowner electrical permits, installed services and passed inspections several times.

 

[goldbrick]

If you use conduit and THWN-2 wire, the conduit needs to be continuous from the breaker box to the receptacle. There can be boxes, etc along the way but the entire routing for the wire needs to be enclosed. You will also need to fish the wire through that 50' run after the conduit is installed.

It would probably be much easier to run NM-B or UF cable inside and then transition to conduit (using a junction box) before the outdoor run. If you use UF (or SER) cable you don't need to splice the wires. If you use NM-B you will need to splice to some sort of outdoor rated wire before the wire goes outside the house.

 

[Flyct]

If you use conduit and THWN-2 wire, the conduit needs to be continuous from the breaker box to the receptacle. There can be boxes, etc along the way but the entire routing for the wire needs to be enclosed. You will also need to fish the wire through that 50' run after the conduit is installed.

It would probably be much easier to run NM-B or UF cable inside and then transition to conduit (using a junction box) before the outdoor run. If you use UF (or SER) cable you don't need to splice the wires. If you use NM-B you will need to splice to some sort of outdoor rated wire before the wire goes outside the house.

If you use NM-B or UF (Romex) you will need at least 6 AWG for 50 amps. 6/3 w ground is tough to work with. I had to use it to wire in an EMS in my 50 amp RV. It comes with 3 stranded wires (Red, Black, white) and one bare solid wire for ground.

Using 8 AWG THWN(-2) is rated for up to 55 amps. There’s no restriction not allowing you to run THWN in PCV conduit before assembling and glueing the sections.

I can’t see ever myself attempting to pull 6/3 UF trough any conduit. It’s VERY STIFF. If you plan on using 6/3 UF in PVC conduit I suspect you would need to significantly upsize to conduit probably to 1-1/2” to meet the fill 53% Max fill requirements and it would be a bitch to pull.

6/3 with ground UF https://www.amazon.com/UF-Underground-Feeder-Direct-Burial/dp/B074V7Z54X/ref=sr_1_4?keywords=6%2F3+wire+with+ground+uf&qid=1637462135&sr=8-4

 

[wwhitney]

Using 8 AWG THWN(-2) is rated for up to 55 amps.

That's the 90C ampacity which is very difficult (but not impossible) to reach in practice. Far more commonly the limit is the 75C ampacity, or 50A.

There’s no restriction not allowing you to run THWN in PCV conduit before assembling and glueing the sections.

NEC 310.18 Raceway Installations says:

(A) Complete Runs. Raceways, other than busways or exposed raceways having hinged or removable covers, shall be installed complete between outlet, junction, or splicing points prior to the installation of conductors.

Cheers, Wayne

 

[Flyct]

NEC 310.18 Raceway Installations says:

(A) Complete Runs. Raceways, other than busways or exposed raceways having hinged or removable covers, shall be installed complete between outlet, junction, or splicing points prior to the installation of conductors.

Cheers, Wayne

Thanks for that reference. Like I stated, I’m not a pro.

Here’s a good YouTube video for the Original Poster to understand what’s involved. Even this pro couldn’t comply with NEC 310.18 at the end and had to modify to get 6/3 Romex through the conduit. https://youtu.be/tBxGo0qveNs

JR

 

[wwhitney]

I had a typo, the section is 300.18(A). And the next sentence is "Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment."

Cheers, Wayne

 

[GerryAZ]

Thanks to Wayne for all of the clarifications. I will add that most EVSE's pass a very small current to ground to verify integrity of the equipment grounding conductor. Some older EVSE's intended for hard wiring pass enough current to ground to cause a branch circuit GFCI breaker to trip (more than 5 mA) so their supply circuits cannot have GFCI breakers (and their installation instructions say not to use GFCI supply breakers). Newer EVSE's have ground test currents lower than 5 mA so they will not inadvertently trip GFCI branch circuit breakers.

 

[pr0lab]

Happy Thanksgiving everyone who is celebrating.

I installed the 6/3 uf/b cable but before connecting to the circuit panel I wanted to ask about bonding ground and neutral wires. I have two buses and the circuit panel but they are mostly filled with wires from other cables coming in to the panel.

Can I insert the neutral and the ground along with other wires to the same insert and not an empty one? I understand that they all share the same bus and they connect this way with each other to close the circuit so the answer is yes? but I believe I read somewhere that I should keep the ground and the neutral separate in different wholes on the same bus.

Thank you!