Upgrading the Panel

[Jagmandave]

I'm in the process of planning for about a 25 X 25 addition to the back of my house, which will be my shop. It will have a roll up door between it and the existing garage and the garage will go back to having cars parked in it - especially the bride's car!

The house was built in '64 and only has an old 100 amp panel, so I'm planning to upgrade to a 200 amp service, as I will be adding quite a bit of electrical load - including the possibility of a charger for an electric car.

OK, so here's the question. Put the new panel where the old one is and run a sub panel service to the new shop, or put the new 200 amp service to the new shop and run service to the old panel from it and leave the existing panel right where it is.

Advantages of running the main service to the addition is that it's a lot closer to the pole in the back yard, and I only have to install one new panel. On top of that the current service is only tied to the house with strain relief, I'm thinking they'll want to upgrade to a regular service head on a pipe, which will be difficult in its current location. At least I think that's how it would go. I could just keep the old panel in place and I wouldn't have to buy a new one for the house with all new breakers and such.

Disadvantage of running the new service to the addition is having to run 100 amps worth of cable to the old panel - which I guess I would have to do anyway, to serve the sub panel in the garage if I go the other way around.

Thoughts from the sparkys onboard?

 

[couch67]

I would put 200 in the new space, and feed the 100 amp as a subpanel. I did exactly this in our place about 20 years ago when we put on an addition.

 

[u2slow]

I like the strategy of all new 200A in a fresh place, and re-feed the old panel. I didn't do many service upgrades as a contractor, but did exactly that for most of them. IMO, its generally nicer to have a main panel in a 'utility' space anyway. Its also easier for a homeowner to do since the power's not out while you're installing most of it. Sometimes, rules, landscaping, or renovations have made the existing service location unsuitable for upgrade.

You can free up space and capacity in the 100A (should you need it) by relocating a large circuit, or two, to the new main panel. Even if you do change the old panel at a later date, you won't be without power entirely while you do it.

 

[sberry]

Yup, it aint gotta be like the old if there is a better way to do it.

 

[Jagmandave]

Wow, thanks for the replies, glad to hear my idea is not completely off base....

As my plans for the shop get finalized I'll be back to ask more direct questions.

I'm thinking I could do all the new install and then only have to be without power when I switch over from the old service to the new, then tie them together.

Just had another thought, I could also tie my genset into the old panel as most of those circuits are for the house anyway......then disconnecting the main on that panel would also separate me from the grid

 

[alfredeneuman]

Look on the label inside the panel cover on the house.
If it says "For Service Equipment Only" it has the neutral permanently bonded to ground and can't be used as a subpanel.
If it says "Suitable for Use as Service Equipment" it can be used but you may have to remove the bonding screw from the neutral bar to the enclosure.

 

[Jagmandave]

Considering the house was built in 1964 do you think the panel will have that label? And in fact I think the neutral and ground are bonded together....

 

[jeepxj]

200 in new space feeding old panel as a sub panel. may need to replace old panel as well.

 

[jeepxj]

Considering the house was built in 1964 do you think the panel will have that label? And in fact I think the neutral and ground are bonded together....

a panel swap on top of all the other work they are doing won't add terribly much to the bill.