ECN Forum Forums General Topics of the Trade General Discussion Area 400 amp panel upgrade

aldav53,

Suggest you do a Load Calc first (as already suggested), and submit it to the PoCo (Utility Power Company).

Do this so they can take into consideration the "Flicker Factor" for the Heat Pumps (if they are not already existing and running).

PoCo may upgrade the service feeders, and if necessary, increase the Transformer's size.

Your Client may have to pay for the feeder upgrade, but not the Transformer upgrade (unless the PoCo finds the flicker factor too excessive and the current load on the Transformer is less than 130%).

Definitely suggest load calcs are done - and maybe done "Heavy"
(higher than normal figures)
on one calc to compare the results.
Figure an ample "Future Load" value on each calc.

You may be fine with the currently used 200 Amp service (panel and / or service feeders).
Upgrade to 400 Amp size if necessary
(or Client demands it!).
Compare current load demand against projected demand, and see if panel / service feeders need to be upgraded.

If the service panel sucks, change it!

I have only used the Square D 400 Amp Residential Service Panel - the one which is a 320 Amp Continuous rated, uses cl 320 KWH Meter, and has (2) 200 Amp 2 Pole breakers (1 for remote Sub Panel, 1 for 200 Amp bus kit within the Panel Assembly).
Had no idea that any others existed (with a 400 Amp bus kit!).
Are these listed for EUSERC (sp??) usage?

Scott35

As long as the load calc is within limits of the 200 amp panel, adding a 100 amp subpanel to it should be ok. Do they make a subpanel smaller than 100 amp? This is a possibility too.

I'm not sure I completely understand your situation so maybe I have misunderstood. The cheapest method to use and still ensure plenty of capacity is to simply use a 400A meter socket and feed out of it twice to two separate 200A panels. You would have to make sure you order lower lugs for the socket that allow two wires in each. Since nobody else has suggested this relatively cheap, simple remedy, I can only assume that I am misinterpreting your description.

Not sure what you mean by a 400 amp meter socket. This would be a 400a outdoor panel using a panel-meter combo or all-in-one, with a 200 amp main and another 200a breaker to feed another 200a subpanel.

How old is the house and what is the actual SEER rating on the A/C’s. I had an almost identical situation recently. I replaced an older 200A service with the same and added two 100A sub panels. One was side by side of the main and the other was installed near the guest house that was just built. The pool company also added another 70A Subpanel after the fact near their equipment. Haven’t seen or heard of any problems with flicker at this job or others like it. You do have to make sure that you have proper voltage from the utility under load (both before and after you do the work) and the actual loads need to remain below the main breakers rating. Yes the panel loads sound excessive but most of it is redundant and mainly for show.

Most small residential sub panels are rated for max 125A but you can always use a smaller breaker to lower the costs when 125A isn't really needed.

Looks like I'll be upgrading to the 400 amp service. I figured approx 138 or 170 amps on the exhisting service (not sure if it has the heat strip supplement on the 2 heat pumps).
He will also be adding an addition with a 72 amp load figured by the Arch. So with adding a 50a spa, a 240 20a water fall and the addition it is over the 200 amp service. I will probably install the 400 amp panel at the exhisting side of the house and add the 200 amp sub panel on the back of the house. Which means possibly piping through the garage all the way to the back.

I was thinking the same as triple. Unless there is a reason I missed such as no space for another panel side by side or the second panel is prefered in new location.

Just get 1 400 Amp pedistal WITH NO main breaker disconect for less than $400. Put that about where the old pedistal was with some sort of 90, 90/45, back to back, or Mogal LB set up. Come out of it twice with 2" (for us it is rigid) into 1 exsisting 200 amp panel and 1 new 200 amp panel.

I would think you could do this faster because you don't need to remove the old panel and cheaper than other ideas.

Tom

Tom and Triple

Since he is in Arizona this service must meet EUSERC requirements. Among other things you are not allowed to bring underground service conductors directly into a standard meter socket. An approved underground pull section must be provided for the utility to terminate their service conductors. The parts to build this service would cost more that purchasing a readily available combination service entrance device which has a pull section, meter socket and load center in one box.

We do things a little different here in the West compared to the rest of the Country.

Curt

Don't need any of that. The power co has to pull in new feeders to the panel and once I change it out they will come back to reconnect.

Caselec, are you saying that the power company wants a place to terminate wires underground before the metersocket? What is their reasoning for not wanting to terminate at the meter socket itself?