Convert Main to Sub and Add a Second Panel?

[NOVA87Wrangler]

I am working on my garage/workshop addition finally and want some advice on my plan for power. The addition is going to be two stories, lower level is garage/workshop and upper level is master suite.

Currently my house has 150 amp service (upgraded from 100 about 8 years ago just before I moved in). I had a load calc done for the new circuits being added and result was the electrician advising upgrading to 200 amp service. The location of my meter is the opposite corner from my addition so I was already planning on doing a subpanel, but the cost to upgrade to 200 amps from 150 is about $3000 around here which is just too much to stomach. I could do it myself but SWMBO isn't that comfortable with it. Also, with the way my basement is finished it's going to make it a pain the *** and with EVERYONE one home due to the "Rona" losing power for a full day with teleworking and kids is already ******* of the wife.

So I was thinking that maybe the easier, cheaper option would be to install my second panel and run wire to the meter and install a main disconnect making my current panel and the second panels both subpanels (or "remote distribution centers"). I know I would have to install ground bars, separate neutrals, and remove the bonding screw in the current panel. But would it be ok to have a main disconnect fused at 200 amps with 2 subpanels, one with 150 amp breaker and the other with say 100 amp?

 

[pattenp]

Yes, but you don't need to add additional ground rods for the subpanels. Ground rods are only needed off of the first disconnect location.

 

[wyliesdiesels]

you will need a dual lug disconnect.

the other thing you'll have to move is the GEC from the ground rods and the plumbing bonding wires from the now subpanel over to the new main disconnect.

 

[sberry]

I might be inclined to figure out if I really needed upgrade.

 

[mike93lx]

What in your house is using that much power? Just curious. If it got by on 100a for some period of time, there must be some significant addition.

Around here, the POCO won't change anything on their end for an "upgrade" to 200. Not the overhead feeder nor the transformer. So it really isn't getting you anything if you aren't already tripping the main

 

[NOVA87Wrangler]

thanks for the replies. Just to double check myself, I want to do some of the work before the main disconnect is installed so make that process easier/faster. Is there any reason i couldn't separate grounds and neutrals in the panel now as long as I keep the bonding screw in there? Want to move any neutrals from the grounding bars if there are any.

And for the GEC, I'll double check but I don't think there's any rods, it's only grounding to the plumbing. I was planning on installing grounding rods for the new main disconnect and then running a wire from the ground in the existing main panel to the new disconnect.

Regarding the need for that much power, the master suite part of the addition will have it's own electric heat pump for HVAC, I want to have some capacity to also add HVAC to the workshop/garage down the road too. Add in a couple 220 lines for welder/air compressor/future electric car charger. Just want to future proof now. And the POCO is already coming out to disconnect and bury the lines since I'm doing a small mudroom/front porch where the overhead lines currently enter.