[crackers8199]

for the past 4 years, my 2013 volt has happily been charging every night via a clipper creek LCS-20 that i installed a plug on and plugged into the 14-50 outlet in our garage. now that i've picked up my model 3, the tesla will use that 14-50 to charge every night, and the volt has become our second car and moved to the other side of the garage.

our main electrical panel is outside, just on the other side of the wall where the volt current parks. on the inside of that wall, next to the volt, is a subpanel inside the garage which is run off a 50amp breaker from the main panel. that sub panel runs some of the lights/outlets inside the house (it's seemingly pretty random what is wired to the sub panel and what is wired to the main panel outside), and has room left for a single double pole breaker (or two single pole breakers).

so, that leads to my question...can i use that open slot on the sub panel and hard-wire the LCS-20 to a newly installed 20 amp double pole breaker? if i were to use the sub panel i think i can do this myself, where if i had to wire to the outside i'd probably go a whole different route and just have a larger line run for either another 14-50 or a 100 amp panel inside for future proofing...but that's way more money than i want to spend right now. also, i'm not comfortable trying to tap into the main panel outside and/or run wires through the outside wall to it, so i'd have to hire someone to do it (even more money).

if i can get the LCS-20 back into operation and avoid having to charge the volt on 110 every night without having to spend too much money (i.e. just supplies since i can do the install to the sub panel myself), that'd be my first choice right now.

thoughts? questions? concerns?

 

[jcanoe]

You will need to consult an electrician to see if your existing sub panel can support the load of the additional 20 amp double pole breaker.

Since you have a sub panel inside the garage you should not need a separate service disconnect only a junction box for connecting the LCS-20.

 

[lagagnon]

If you're going to do it yourself without an electrician then I would first find out what the other circuits are on that sub-panel and determine what if any large appliances might be frequently in use on those lines and how many lights are normally on those lines and the wattage. Add up all the watts possibly used on each circuit at peak use times and ensure that even if you say have a hair dryer, kettle and toaster on plus the 16A draw from the Volt that you won't be exceeding the 50A total (less about 20%) for the entire sub-panel.

 

[FI Spyder]

If you're going to do it yourself without an electrician then I would first find out what the other circuits are on that sub-panel and determine what if any large appliances might be frequently in use on those lines and how many lights are normally on those lines and the wattage. Add up all the watts possibly used on each circuit at peak use times and ensure that even if you say have a hair dryer, kettle and toaster on plus the 16A draw from the Volt that you won't be exceeding the 50A total (less about 20%) for the entire sub-panel.

In other words everything (watts) added up should not be above 80% of the 50ampx240V= 12,000 watt available. I would check with your governing body to see if you need a permit and inspection to add the breaker to the sub-panel. If you do and don't get it, it will invalidate your house insurance. Added expense but if you do the electrician would have to get it anyways and add it to your bill.

 

[Don M]

If you're going to do it yourself without an electrician then I would first find out what the other circuits are on that sub-panel and determine what if any large appliances might be frequently in use on those lines and how many lights are normally on those lines and the wattage. Add up all the watts possibly used on each circuit at peak use times and ensure that even if you say have a hair dryer, kettle and toaster on plus the 16A draw from the Volt that you won't be exceeding the 50A total (less about 20%) for the entire sub-panel.

Good answer

So long as your sub-panel isn't already near it's capacity with loads which will be in use while you're charging, then you can add a double pole breaker in the vacant space and hardwire your EVSE into a new outlet box

Don

 

[wws]

When doing your load calcs, note that the 2nd Gen Tesla UMC only draws 32 amps, instead of 40, when using the 14-50 adapter. This because it is Code-legal to have a 14-50 on a 40 amp circuit.

 

[crackers8199]

When doing your load calcs, note that the 2nd Gen Tesla UMC only draws 32 amps, instead of 40, when using the 14-50 adapter. This because it is Code-legal to have a 14-50 on a 40 amp circuit.

this wouldn't matter, the 14-50 is wired direct to the outside main panel. it wouldn't be a factor in the subpanel calculation.

 

[KenC]

You seem to imply that the 50amp sub panel runs some lights/outlets. If that's actually the case, then it should have little trouble handling the CC LCS20. Your idea makes sense, and should be a relatively easy project. You can charge the Tesla on the 14-50 from the main panel, and the Volt from the LCS20 on a sub panel.

 

[crackers8199]

bringing this thread back from the dead, as finally a little over a year later i'm finally getting around to perhaps doing this.

i did a little more research (and planning to do more this weekend perhaps, with all of the outlets in the house to find out for sure exactly what is on what outlet)...here's what i've come up with so far:

the main panel has all of the heavy loads (other than forced air, see below), such as AC, fridge, microwave, dishwasher, etc. pool subpanel and 14-50 that is now being used by the tesla are also wired directly to the main panel.

it appears that all GFCI in the house (all bathrooms, all kitchen outlets and garage outlets) are wired to the main panel as well (will get further details on this when i go through the house and flip each breaker one by one to figure out exactly what is where).

the subpanel has most of the other outlets and lights for the entire house, plus the forced air unit. i'm struggling on doing a load calc for this, because it seems that based on what i've read i should take the square footage of the areas covered by the subpanel and multiply by 3, but i'm not entirely sure where that should be done. for example, it seems the kitchen and bathroom outlets are wired to the main panel, but the lights may be on the subpanel (again, not 100% sure). at this point i'm just going off of the labels that are on the subpanel and main panel, won't know for sure until i actually test everything.

when doing a load calc - if the lights are on the subpanel but not the outlets, do i still need to multiply that entire area by 3? if so, it's not likely the subpanel has enough room on it as that would cover pretty much the entire square footage of my house and would put the load right now (if i've done this right) at 36.25, which is under the 40 amps (80% of 50) i've got available but not enough room to add the 16A draw of the LCS-20.

 

[FI Spyder]

Never heard of the multiply by 3 rule. Here you add up the wattage capacity of the breakers and it should not be over the wattage of the panel (wiring and main breaker). For my house that would be 200 x 240 = 48,000 watts. A sub panel is a part of this total load. The load should be no more than 80% of capacity. To do electrical work you need a permit. This covers two or more inspections to make sure the work is done correctly. Talk to your electrical inspectors if you are unsure before hand. When I renovated my house, I added a subpanel in the garage and there where a number of questions of what I wanted to do that weren't covered in my code book so I talked with them before doing the work (about 8 instances actually). If you don't get an electrical permit and inspections and there was an electrical fire you wouldn't be covered by your fire insurance (it would be ruled null and void). It's cost is based on the cost of work done (estimated) and for two inspections (before closed in and prior to being turned on) it cost $135 (consultations were free). It's a minor cost compared to hiring an electrical contractor (who also has to get the work approved). That's the way it works here in Canada (I've done major additions in Calgary and here, all the work approved).