200 Amp main adding two sub panels

Status
Not open for further replies.
C

CLowe628

Member
Location
Mass
Occupation
Electrican
I have a home owner with a 200 amp main house panel and just added two additions. They want a 100amp sub panel for one and a 60amp for another. Existing panel has a pool, hot tub, electric stove and 3 AC circuits, plus your basic household circuits. One addition will have A mini split, washer dryer combo and just basic 1 bedroom circuits. The other will have a a full kitchen with electric range, washer dryer combo, forced hot air/AC. Just ball parking, would I have to upgrade the service? The customer doesn’t want to. I’m a commercial Electrican that works off plans all the time and I am doing this on the side. Any help would be appreciated.
 
You need to know what their usage is now, then do a load calculation on the additions to see what the total load is/will be. Or do a load calculation on the existing and one on the additions, then add them together.
 
You need a load calculation. I don't believe that an electrical inspector would sign off on this without one.
 
I answered the question as asked: "ball parking."

In my opinion, a load calc would only be necessary if the goal is to avoid the upgrade.
 
As a ball park guess I suspect the added loads are going to put you into a service upgrade situation.

You cannot tell for sure without doing a load calculation.

220.83 or 220.87 might be of some help in avoiding a service upgrade.
 
Existing 200A panel already sounds maxxed out with a pool, hot tub, 3 A/C compressors, electric range plus "normal house stuff". Is there gas for anything (clothes dryer, pool heater, domestic water heater)? A second electric kitchen and an additional HVAC unit are probably going to put you well over the 200A service limit. Each laundry needs a 1500VA circuit in addition to the big one for the washer/dryer combo unless it uses gas for heat.

Also check what size conductors the utility has run. Mine has 2 sizes for 200A services -- one for houses with heat pumps and one for without. The "without" is quite small. The "with" still seems small to me, and you still end up with some flicker. They may want to know the LRA of the largest compressor. They will do a small bump up for a 400A service. I think mine was 1/0 Al for an overhead drop.
 
If you are doing this "on the side and don't have plans, then you likely don't have a permit. If you are adding two additions without a permit you must be way out in the "boonies".
Like they said, put a meter on it for a while and see what you have. Since it is winter in Mass., you will have to add in the amps or KVA for the AC unit. How about the amps or KVA for the pool pump and heater?

A ballpark guess is you need to upgrade to a 400 amp panel. As said above, your incoming electrical feed may be sufficient to change out to a 400 amp panel. If not, I believe your electric company will upgrade the feeder if necessary. Of course, your electric company will also want the demand load calc and connected load!!!!

If for some reason you customer refuses to upgrade, just tell him its on him if the existing main 200 amp breaker trips. If it does trip, Turn the breaker back on and don't run so many loads at the same time. Or just do the right thing and uprade to 400 amp panel. Panels are pretty cheap these days.

Electrical guys have been wondering since the invention of electricity if their main service panel will have enough power. Nothing new. Even engineers wonder and guess as well every day. They tend to way overshoot just to be safe and take the liability off of themselves.
 
suemarkp said:
Existing 200A panel already sounds maxxed out with a pool, hot tub, 3 A/C compressors, electric range plus "normal house stuff". Is there gas for anything (clothes dryer, pool heater, domestic water heater)? A second electric kitchen and an additional HVAC unit are probably going to put you well over the 200A service limit. Each laundry needs a 1500VA circuit in addition to the big one for the washer/dryer combo unless it uses gas for heat.

Also check what size conductors the utility has run. Mine has 2 sizes for 200A services -- one for houses with heat pumps and one for without. The "without" is quite small. The "with" still seems small to me, and you still end up with some flicker. They may want to know the LRA of the largest compressor. They will do a small bump up for a 400A service. I think mine was 1/0 Al for an overhead drop.
Click to expand...
Yeah I’ll have to do some more digging, I’ve only been to the house once so far, I know it’s a newer underground service, and I gotta find out if the conduit is big enough for an upgrade as well, it’s seeming more and more like I’m going to have to upgrade even though the customer doesn’t want to, going to do a load calculation today and see what I get, thank you for your input
 
powerpete69 said:
If you are doing this "on the side and don't have plans, then you likely don't have a permit. If you are adding two additions without a permit you must be way out in the "boonies".
Like they said, put a meter on it for a while and see what you have. Since it is winter in Mass., you will have to add in the amps or KVA for the AC unit. How about the amps or KVA for the pool pump and heater?

A ballpark guess is you need to upgrade to a 400 amp panel. As said above, your incoming electrical feed may be sufficient to change out to a 400 amp panel. If not, I believe your electric company will upgrade the feeder if necessary. Of course, your electric company will also want the demand load calc and connected load!!!!

If for some reason you customer refuses to upgrade, just tell him its on him if the existing main 200 amp breaker trips. If it does trip, Turn the breaker back on and don't run so many loads at the same time. Or just do the right thing and uprade to 400 amp panel. Panels are pretty cheap these days.

Electrical guys have been wondering since the invention of electricity if their main service panel will have enough power. Nothing new. Even engineers wonder and guess as well every day. They tend to way overshoot just to be safe and take the liability off of themselves.
Click to expand...
I’m going back today to get more info on everything and do a load calcution, I do have insurance and will be pulling a permit, this is a nice house in a nice neighborhood, new customer I’m trying to take it easy on because he’s got a lot more work for me, but if I have to upgrade, I gotta do it wether he wants to or not. Thank you
 
CLowe628 said:
I’m going back today to get more info on everything and do a load calcution, I do have insurance and will be pulling a permit, this is a nice house in a nice neighborhood, new customer I’m trying to take it easy on because he’s got a lot more work for me, but if I have to upgrade, I gotta do it wether he wants to or not. Thank you
Click to expand...
If I had a dollar for everytime I heard this from a (prospective) customer I could retire. Usually they want you to lower your price with the promise of more work. Now why would you want to lose money on more than one job?:cautious:
 
CLowe628 said:
I’m going back today to get more info on everything and do a load calcution, I do have insurance and will be pulling a permit, this is a nice house in a nice neighborhood, new customer I’m trying to take it easy on because he’s got a lot more work for me, but if I have to upgrade, I gotta do it wether he wants to or not. Thank you
Click to expand...
Look at it another way, you might be taking it easy on him by doing it right the first time.
 
Little Bill said:
If I had a dollar for everytime I heard this from a (prospective) customer I could retire. Usually they want you to lower your price with the promise of more work. Now why would you want to lose money on more than one job?:cautious:
Click to expand...
Yep. Dropping price for a potential repeat customer sets a bad precedent.

You can't continue to provide good service if you can't stay in business.
 
Status
Not open for further replies.
Top