How to future proof NEMA 14-50 outlet for wall connector installation in the future?

[coolmanfever]

Hello all.

I am in the process building my home. I plan to install two NEMA 14 50 outlets. Since I only have SR model 3, I don't think that I would benefit from wall charging connector right now. But I want to future proof one of nema outlet to upgrade to wall charging connector in the future.

What instruction and specification should I provide to my electrician?

 

[brkaus]

How much capacity do you have at the main panel? If you can support two 14-50s, I would guess you could support 60a also. You should have them wired using wire sized for 60a (48a continuous).

If you really want to be proactive, you can wire for 100a (80a continuous) in case the CyberTruck supports higher charging rate in the future.

Possibly use a large box and leave a loop of wire in the box that could make it to the HPWC without splicing.

If you think it's only for car charging forever, you could have a 6-50 installed instead. One less conductor (no neutral).

Note: At least in the US, it isn't legal to share two 14-50 on a single circuit. It is also required (in many jurisdictions) to have a GFCI breaker. Those are pretty expensive.

 

[iluvmacs]

Nothing really, unless you possibly want to support higher than 40A charging in the future. For instance, if you want to do 48A charging, have them put in wire good enough for a 60A circuit. Also make sure they run copper wire, not aluminum, and leave some extra length in the wire.

 

[Tessaract]

How much capacity do you have at the main panel? If you can support two 14-50s, I would guess you could support 60a also. You should have them wired using wire sized for 60a (48a continuous).

If you really want to be proactive, you can wire for 100a (80a continuous) in case the CyberTruck supports higher charging rate in the future.

Possibly use a large box and leave a loop of wire in the box that could make it to the HPWC without splicing.

If you think it's only for car charging forever, you could have a 6-50 installed instead. One less conductor (no neutral).

Note: At least in the US, it isn't legal to share two 14-50 on a single circuit. It is also required (in many jurisdictions) to have a GFCI breaker. Those are pretty expensive.

This is good advice.

My opinion is that 100A circuit is well in the region of diminished returns... Even a 60A circuit (charging at 48A) will 100% charge a 150kW battery in 13 hours, which you would do almost never. Here in Canada, 60A circuit can be wired with 6AWG wire. If you surface mount the cable in the garage, you will need to run either conduit or TECK cable.

Key is leaving a loop at the end of the run long enough to cover all contingencies. Remember the adage: the most expensive cable in the world is the one that's 1" too short...

 

[brkaus]

This is good advice.

My opinion is that 100A circuit is well in the region of diminished returns... Even a 60A circuit (charging at 48A) will 100% charge a 150kW battery in 13 hours, which you would do almost never. Here in Canada, 60A circuit can be wired with 6AWG wire. If you surface mount the cable in the garage, you will need to run either conduit or TECK cable.

Key is leaving a loop at the end of the run long enough to cover all contingencies. Remember the adage: the most expensive cable in the world is the one that's 1" too short...

Agree 100a is way overboard for 90%. I went with 50a and we are easily covering 2 cars with a single EVSE. All depends on amount of driving.

 

[doghousePVD]

I would definitely vote FOR the 100 amp circuit, especially if you will have two cars. While the current "little" cars like the 3 can't utilize more than 32 A or 48 A at present, I think there is no question the top Pickup or Roadster will charge at 72A or 80A. Wall Chargers support 80A, as do all Tesla plugs.

Just because you don't need that much power every day doesn't mean sometime you arrive late (date night?) and are leaving early the next morning for a long trip, maybe with a trailer and you don't have to unhitch at a SC.

Lots of folks will disagree. This is a discussion for future proofing, not what the "average" commuter in an existing car wants most of the time.

 

[srs5694]

I would definitely vote FOR the 100 amp circuit, especially if you will have two cars. While the current "little" cars like the 3 can't utilize more than 32 A or 48 A at present, I think there is no question the top Pickup or Roadster will charge at 72A or 80A. Wall Chargers support 80A, as do all Tesla plugs.

I tend to agree. The question isn't really about amperage per se; it's about how many miles of range you can add to the car per hour of charging. That metric changes with both the charge rate (amperage -- or kW, more precisely; but that varies in lockstep with amperage given a fixed voltage) and the energy efficiency of the car. The Model 3 is, if I'm not mistaken, the second most energy-efficient EV out there. (The first generation Hyundai Ionic edges it out by a bit, IIRC; but the Model 3 beats the second generation Ionic.) Thus, you can add a lot of miles per kWh to a Model 3. The Model X is much less energy efficient; it adds only about 2/3 the miles that are added to a Model 3 at any given charge rate (in kW). In the future, there are likely to be even less energy-efficient EVs produced. I fully expect the Cybertruck, Rivian trucks, and so on to be pretty dreadful in that respect. In ten or twenty years, if @coolmanfever (or whoever owns the house at that time) buys such an "electron guzzler" and needs to drive it many miles per day, then it will be desirable to have faster charging available in the garage. Likewise if the garage holds two or more EVs that are charged off of one EVSE. This issue will be more critical if the house is on a ToU tariff with a short period of low rates; in such a scenario, charging quickly will be important. Since we're talking about new construction, when it's relatively easy (and I assume relatively cheap, although I've not looked into it) to put in electrical wiring, it's best to put in something that's as flexible and future-proofed as is practical.

One more thought: If future needs are unknown, would it make sense to run, say, a 100A line to a sub-panel in the garage (if the main panel isn't there already)? That way, it would at least be relatively inexpensive to split off whatever types of lines are required for EV charging in the future, even if only one 40A or 50A line is used initially. Note that I'm not an electrician or in the home construction business, so I have no idea if this is reasonable or cringe-inducing.

 

[ucmndd]

Possibly use a large box and leave a loop of wire in the box that could make it to the HPWC without splicing.

If you think it's only for car charging forever, you could have a 6-50 installed instead. One less conductor (no neutral).

This is what I'd do. Wire one as a proper 14-50. Wire the second as a 6-50 with 6awg conductors in conduit and enough slack to eventually wire it into a wall connector for 48 amps (since the wall connector doesn't need neutral, wire this outlet as a 6-50 instead of 14-50 in the interim).

100 amps, subpanels, etc etc... it's all way over the top. Maybe consider if you're flush with cash and this is your forever home, otherwise I don't see a lot of reason to bother.

 

[brkaus]

With regard to future proofing, 100a lines, multiple outlets, etc the answer is very simple: must meet minimum requirements for the owner and should have a reasonable cost.

One can construct a table of options.

1. 5-15 outlet
2. 5-20 outlet
3. 6-30 outlet
3. 14-30
4. 6-50 / 14-50
6. Wall connector
@ 30amp
@ 50amp
@ 60amp
@ 100amp

Multi-car support
7. Two of any of above outlets 1 through 4
8. Two load shared Wall Connectors @ various amperage
9. Two independent wall connectors @ various amperage.

Then determine minimal requirements based on usage per day, requirement for quick turn around, older car with dual chargers, ones judgement of newer car charging requirements.

With a baseline determined, get pricing for that all the way up to maximum. There is typically a jump over 60a. But, depending on the current electrical situation there could be jumps other places as well if a panel has to be replaced.

If 100a added 10% to the cost, go for it. But if it isn’t needed and makes the cost 3x...

someone might be able to sneak in a $50 conversion of a 5-20 to a 6-20 and meet their needs.

 

[davewill]

Most of this is total overkill. What I would do is size the wire for a 60a circuit, which will be a minimal increment in cost. Then if you decide to go with a wall connector, you can upgrade the circuit to 60a and support 48a charging. Two 60a wall connectors is plenty of capacity for a two car garage.