CT charging revisited

[CostcoSamples]

I second the motion for 100A.

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[DarinCT]

The 100A recommendation is based on them spending your money. While 100A has some merit, are you really ever going to need that charge rate? Are you planning additional loads? Depending on the distance, the cost difference between 60A and 100A may or may not be noticeable. For our house the gap between the garage frame and house frame was dinky and a 100A would have had the electrician chipping at the frames. Everybody's situation is different.

House Tesla run 60A several years ago was $1400. $2200 60A spa run outdoors over 100 feet, trenching **not** included.

 

[Ogre]

If the voltage drops too much you can install a pump.

 

[JBee]

I had conduit run under my new driveway for a second EV charger for my CT. I haven't pulled wire because we don't know what the CT charging wiill be. I know I have asked this before, and that no one really knows the answer (at least, those who have responded), but how about thoughts on the possible maximum current (and hence wire gauge) the CT might need?

In what time periods do you expect to charge the most (peak, off peak, shoulder) and are you going to charge primarily from the grid or mix with solar etc?

 

[Aces-Truck]

I am currently designing for to build a Garage at my house. Like the OP, I am trying to figure out how best to future proof my build for EV charging. I think my setup will be simpler; but not sure. The 200Amp main panel is in my house. The new garage will be closer to the road. My plan is to re-route the incoming power to the Garage, then use buried conduit to run power to the Main panel in the house. So I'll need to have a panel in the garage that splits the power into what runs to the main in the house, and separate line to the EV charger(s) in the garage. So I can run power for one or two EV chargers above ground. But not sure how the panel would work that splits the power in the garage. I would hope I could have service wire come into a 200 amp breaker to continue to the house, and a 100amp service to handle garage wiring. Not sure if I'd need a master switch to kill all power. Still need to discuss options with my electrician.

 

[Ogre]

I am currently designing for to build a Garage at my house. Like the OP, I am trying to figure out how best to future proof my build for EV charging. I think my setup will be simpler; but not sure. The 200Amp main panel is in my house. The new garage will be closer to the road. My plan is to re-route the incoming power to the Garage, then use buried conduit to run power to the Main panel in the house. So I'll need to have a panel in the garage that splits the power into what runs to the main in the house, and separate line to the EV charger(s) in the garage. So I can run power for one or two EV chargers above ground. But not sure how the panel would work that splits the power in the garage. I would hope I could have service wire come into a 200 amp breaker to continue to the house, and a 100amp service to handle garage wiring. Not sure if I'd need a master switch to kill all power. Still need to discuss options with my electrician.

We have a similar setup. We have a panel outside our house where the power meter is and there is a breaker panel there where Power company power switches to our site, then a second panel inside our house.

where is your meter now?

 

[Aces-Truck]

We have a similar setup. We have a panel outside our house where the power meter is and there is a breaker panel there where Power company power switches to our site, then a second panel inside our house.

where is your meter now?

Meter is on the house. But lines come from a pole at street, to a pole on our property not far from the site for now garage, to mast 2/3 up 2-story house. There's enough wire length between our pole and house, to reach new garage.
We are likely going to do solar on the garage. That will require two meters at garage.

 

[ajdelange]

My plan is to re-route the incoming power to the Garage, then use buried conduit to run power to the Main panel in the house. So I'll need to have a panel in the garage that splits the power into what runs to the main in the house, and separate line to the EV charger(s) in the garage.

This means that your "service entrance" will be in the garage.

So I can run power for one or two EV chargers above ground. But not sure how the panel would work that splits the power in the garage.

The split will be done in the "service equipment" after the service disconnect. This can be done with splices, multi port lugs etc. From this point wires will be run to the panel that serves the house and to a panel that serves the garage. Either or both of these can have sub panels wired to them as required for EVSE or anything else.

I would hope I could have service wire come into a 200 amp breaker to continue to the house, and a 100amp service to handle garage wiring.

You would wire from the service entrance to the existing 200A panel and also to a separate 100 A panel in the garage. Now, of course, you will have to be sure you have 300A service. You will also need to remove the bonding jumper in your existing house panel and install one at the service entrance.

Not sure if I'd need a master switch to kill all power.

Yes, you will need a service disconnect, just as you do now (it's the 200A breaker in your main panel.)

Still need to discuss options with my electrician.

Yes, you absolutely do. I just gave you a bunch of free advice. Consider it worth every penny you paid for it.

 

[ajdelange]

We are likely going to do solar on the garage. That will require two meters at garage.

Do you have some kind of byzantine rate tariff? Around here there is one rate and the (single) meter runs forward or backwards according as to whether we are taking power from the grid or supplying power to it.

 

[Aces-Truck]

This means that your "service entrance" will be in the garage.

The split will be done in the "service equipment" after the service disconnect. This can be done with splices, multi port lugs etc. From this point wires will be run to the panel that serves the house and to a panel that serves the garage. Either or both of these can have sub panels wired to them as required for EVSE or anything else.

You would wire from the service entrance to the existing 200A panel and also to a separate 100 A panel in the garage. Now, of course, you will have to be sure you have 300A service. You will also need to remove the bonding jumper in your existing house panel and install one at the service entrance.

Yes, you will need a service disconnect, just as you do now (it's the 200A breaker in your main panel.)


Yes, you absolutely do. I just gave you a bunch of free advice. Consider it worth every penny you paid for it.

Understood about the Bonding Jumper. Ground rods will be at the new garage, so they should not have multiple paths to ground. New Ground wire for house panel will run in conduit to ground at Service entrance.

There are two more considerations I need to figure out.
1) I can't find breakers bigger than 200 amp. Woul the service entrance have a 200 amp for the run to the house and a 100 amp running to my garage subpanel, with just a disconect (not a breaker) to kill power to everthing?

2) I'd like to be able to use a generator to power specific breakers in the house. I originally had planned to install a Manual Transfer Switch Kit at the house, for specific circuits. With CT coming (eventually) I"m debating about having the conection for the generator at the garage, and run sepatate wire between garage and house for the manual switch. Trying to make it so I could eventually power the house using CT instead of a gas generator, for short outages.

 

[Aces-Truck]

Do you have some kind of byzantine rate tariff? Around here there is one rate and the (single) meter runs forward or backwards according to whether we are taking power from the grid or supplying power to it.

I"m not sure why they require the two meters. I"ve seen this on every new solar panel install, in our county. I believe on is total power used from grid, while other measures what you send into the grid. They no longer pay for excess solar output. Instead they track the output to offset your bill. Once a year they reset everything. My Brother in law wanted to be sure he didn't give free electricity to the utility, so he purposely under bought on pannels.

 

[ajdelange]

Understood about the Bonding Jumper. Ground rods will be at the new garage, so they should not have multiple paths to ground. New Ground wire for house panel will run in conduit to ground at Service entrance.

The ground itself can be distributed (although I did run into an inspector that did not understand this). The requirement is that there must only be one interconnection between the ground and neutral and that must be at the service entrance. Be guided by you local electrician wh knows the local code and local inspectors.

There are two more considerations I need to figure out.
1) I can't find breakers bigger than 200 amp. Woul the service entrance have a 200 amp for the run to the house and a 100 amp running to my garage subpanel, with just a disconect (not a breaker) to kill power to everthing?

There are breakers bigger than 200A made but I'd expect your guy to install a fused disconnect.

2) I'd like to be able to use a generator to power specific breakers in the house. I originally had planned to install a Manual Transfer Switch Kit at the house, for specific circuits. With CT coming (eventually) I"m debating about having the conection for the generator at the garage, and run sepatate wire between garage and house for the manual switch. Trying to make it so I could eventually power the house using CT instead of a gas generator, for short outages.

The most convenient is a "whole house" generator permanently wired to an automatic transfer switch. It doesn't have to be a 200A generator if equipped with automatic load shedding modules. I see your electrician gleefully rubbing his hands together.

 

[ajdelange]

I"m not sure why they require the two meters. I"ve seen this on every new solar panel install, in our county. I believe on is total power used from grid, while other measures what you send into the grid.

I have heard of such things but never encountered it.

My Brother in law wanted to be sure he didn't give free electricity to the utility, so he purposely under bought on pannels.

Bit off his nose to spite his face. BTW his excess goes to his immediate neighbors (but they pay the utility for it).

 

[Crissa]

2) I'd like to be able to use a generator to power specific breakers in the house. I originally had planned to install a Manual Transfer Switch Kit at the house, for specific circuits.

That's the reason to use a sub-panel.

-Crissa

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