Electrical – Questions regarding the plan for new 50A circuit (with pictures)

circuit breakerelectricalelectrical-panelnecreceptacle

Overview

Pictures/diagrams at the end. I will pull permits and would like to do this correctly. I will be disconnecting an unused 40A circuit and replacing it with a new 50A circuit to my garage for a NEMA 14-50 electric vehicle (Tesla) charger. The wiring specifications from Tesla say to use a neutral wire for the NEMA 14-50. This circuit will be submetered for time of day rates specific to the electric vehicle only.

Plan

I will remove the 40A double pole breaker, cap that circuit's wires, and install new 50A double pole breakers
I will use 6-gauge THWN wire, attaching ground to ground bar, neutral to neutral bar, one hot to each side of the 50A double pole breaker
The circuit runs to the exterior with LBs at each egress/ingress, passing through PVC conduit and a submeter on its way to the garage
It runs through studs in the garage wall, exiting at the plastic box for a NEMA 14-50 receptacle

Questions:

Do I run individual insulated wires or should all four insulated wires also be sheathed? Relates to my next question regarding the neutral wire. Again this will pass through an exterior raceway so therefore a "wet location." I assume all four are sheathed together.
The wiring diagram for the submeter only has lines drawn for the two hots. I've drawn in how I believe it should be wired. The neutral bypasses everything in the meter, going straight from the neutral bar at the main panel to the NEMA 14-50 receptacle. Is this correct for the neutral?
The ground wires are stripped 3/4", attached from ground bar at main panel to the ground lug (?) in the meter, then again from ground lug in meter to the receptacle. No ground attached to the plastic outlet box. Is this correct for the ground?
I plan to exit the house at LB which goes down into submeter, putting the new submeter next to the existing meter (pictured), then continuing down through the conduit to the garage. If I drill holes through studs inside to do this, do I need bushings?
The exterior PVC conduit will rest on the masonry foundation. Do I need to secure the conduit to the masonry?
Should I use 1" PVC conduit, given 4 6-gauge wires?
What else that I didn't mention will make this easier/safer?

Meter diagram

Interior

Exterior

Garage

Meter panel

Meter panel instructions

Best Answer

Answering your questions in turn:

You will be using individual wires in the conduit here -- there's no reason here that merits wrestling a fat, annoying cable down a conduit! All four wires, however, will get pulled through the conduit as a group -- you can suck a string (tie a plastic bag on the end) through the conduit once it's together that you can then use to pull the wires through.
You are fine on the neutral here -- a meter for 120/240V split-phase service doesn't need it. Simply nut the line and load neutrals together with a suitable wirenut (or a mechanical screw-terminal splice connector) at this point.
Your proposed grounding scheme is also fine given your choice of conduit -- I would suggest running a bare ground wire instead of an insulated one, though, as that saves a bit of space inside the conduit.
Since you are running conduit through the studs instead of a cable, you will not need bushings of any sort to run the conduit through holes in the studs. I suggest running the exterior conduit above the window, by the way; that way, you don't have to try to fit a conduit behind your gas meter.
You do need to secure the conduit to whatever it is sitting against at 3' intervals, yes. Strapping to every other stud works if you are running against the siding with studs 16" O/C -- for studs 24" O/C, simply attach a conduit strap to each stud, through the siding. If you do decide to attach the conduit to the masonry, use masonry anchors or fasteners for the conduit straps, on 3' spacings.
1" is a suitable size for the run you have planned, but PVC may not be the correct material -- you may prefer EMT instead, although you'll want to transition to LFMC for the compound bend at the garage-end of the outdoor run instead of using conduit bodies for that -- either that, or bend EMT or PVC to fit using a conduit bender.
If you're going to do the run over the top of the window, then I'd mount the meter pan so that its bottom edge lines up with the top edge of the window. That means you can simply run the conduit out the knockout on the left side of the meter pan.

Related Solutions

Electrical – Provisioning for a hypothetical electric car

See SAE J1772

In the 2009 standard, two charging levels are defined.

            Voltage  Phase          Peak current
AC Level 1  120 V    Single phase   16 A
AC Level 2  240 V    Split phase    32 A (2001)
                                    80 A (2009)

Nissan say

Most Nissan LEAF owners recharge their cars at home. The 6.6kW charger option lets you charge your Nissan LEAF at home in just 4 hours using a 32A Home Charging Unit

For that option you'd need a dedicated 240 volt 32 amp circuit.

Until you actually have an electric car it may be best to leave that circuit terminated in a junction box of some sort and leave the fitting of a charging-unit until later. You probably shouldn't fit a regular 240 V 32A outlet because the J1772 system requires some intelligence be built in to the supply side (the charging unit).

In some countries the government will pay you up to $1600 to have a charging point fitted in your garage. If you live in such a country, it might be worthwhile taking advantage of such offers whilst they are still available.

Electrical – Is a 240vac (2 pole) outlet a “single phase receptacle”

If you hard-wire the EVSE unit, then you're covered because the unit has GFCI built in and you never have an open unprotected receptacle.

Presumably you are talking about a residential application in the U.S., since you seem to be doing it yourself and you are referencing the 2017 N.E.C.

This applies whether your 240V supply is single-phase or 3-phase (in which case it will probably be 208V).

As a curiosity, it might be worth mentioning that if you're dealing with a 3 phase service typical of commercial installations (say you're doing this at a rented commercial office or store space rather than at home), then your service is probably 3-phase with neutral, in which case your outlets will either be 120V, or 208V (there is 120V of potential from any of the phases to the neutral, and 208V from any of the phases to another phase).

In a residential situation, you are served by a single phase (from the 3 phase distribution lines), which is stepped down to 240V in the transformer outside your house. This is split, in the transformer, by a center tap neutral into a pair of 120V legs. This means you get 120V from either pole to the neutral, and 240V from pole to pole. But either way it is still only 1 phase.

Sidebar...

The poles of your residential transformer are 180 degrees out of phase with each other, because the AC sine waves are shifted 180 degrees apart. I believe this is one of the sources of occasional confusion, and this plus the fact that both circuits derive from one phase is one of the reasons that some people refer to the 120V legs as "phase legs", and is also why some people sometimes seem to perceive "phase leg" slightly differently than other people. The bottom line is that this entire setup is a branch circuit off of just one phase of the nearest 3 phase transformer that ties you into the long haul power transmission lines that serve you. Thus, the entire 240V circuit that feeds your house, and both 120V legs of that circuit, are all one phase. And yet the two 120V legs actually are out-of-phase from each other.

Summary

But again; if you are connecting the EVSE (Electric Vehicle Supply Equipment) unit to an approved power source, and you hardwire it in, then you are covered by the GFCI built-in to the unit because you don't have an exposed, unprotected receptacle.

If you run power to a receptacle that you then plug the EVSE into, then you're probably required to use a GFCI breaker because you have created a situation where there may be an open receptacle in an area that requires GFCI protection.

Best Answer

Related Solutions

Electrical – Provisioning for a hypothetical electric car

Electrical – Is a 240vac (2 pole) outlet a “single phase receptacle”

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