Service size

I’ve never dealt with this, but just curious… am doing a new construction phased inspection. They have just gotten the service panel up, but not connected.

This is a 2500SqFt 1 story home, 4BR/3BA, with the typical appliances, and a pool and spa.

I noticed the panel is set up as a 150Amp service. Should I recommend it be 200Amp? As I said, it’s not complete yet, and the client could talk it over with the contractor, but I’m hesitant to question the plans.


Hi Andrew,

150 amps isn’t wrong, 100 amps is the code minimum for a single family, however what did the plans call for?

BTW it’s likely that only changing out the main breaker would make it a 200 amp supply as most electricians install a large enogh SEC to supply that.



If your going to be doing more new home inspections, learn how to do load calculations. In my part of Canada, I’ve found 1600 sq ft split entry homes with electric heat/no AC that were within code at 100 amps…actually with 2,500 watts to spare on the heat.

Andy, Does this home have gas available? The pool and spa heater, home furnace, oven/stove could all be on gas and not really affecting the electric usage that much. More information would help.

You would be surprised how small the electrical service demand factor can calculate to be. For instance my house is 3000 sqft under air with the following: your regular kitchen appliances, a 5 ton & 1 1/2 ton split units, 15 kw of electric heat, 4.5 kw water heater, dryer, freezer, 1 1/2 hp pool pump, electric heat pump pool heater, 3/4 hp whirlpool pump, and electric dryer. Using the NEC optional method it calculates out to be only 177 amps.
A 150 amp service should be sufficient for the home, If the meter module is rated 200 amps with a 150 amp main which the electrician could change out to a 200 and the feeder to the panel is not to long it would not be expensive to upgrade for future expansion or additional electrical items.

Hi Andy,

The IRC shows you how to calculate the load size needed.

I’m aware of how to do the calculations, but this house is just roughed in, without any appliances, no HVAC installed yet. It is ready for drywall. The service panel and meter base are physically attached to the house, but not wired. The main electrical distribution panel is in place, but no breakers installed. There is a separate subpanel for the pool equipment, but not marked as to the power rating there. I just happened to open the service panel, and saw that the main breaker is 150.
I realize 150 is sufficient for most applications, and well within code. My reason for asking is that at this stage, it should be very easy and cheap to change to 200 amp - most likely just switching out the main as Gerry said. If I wait until all is installed, it would be much more complicated, and unlikely to get the builder to easily go along.

And to answer, this house is all electric, with plans for high efficiency heat pump, dishwasher, all the appliances, plus a pool and separate spa. The pool will be heated with its own heat pump.

Without doing the calculations, with the timing, I thought I’d suggest (emphasize on suggest !) they upgrade it to 200 amp service.

It can’t hurt to recommend a 200 amp service. I would say its cheaper to do it now then in the future. The difference is the cost of 2/0 cu compared to #1 cu. The breakers should be a wash.

Thanks for all the advice, guys.
This client is kind of funny - a real nice guy. He placed the contract to build this home, it’s a Ryland home. Then, after signing, he went and researched Ryland - found that they had close to 50 complaints filed on them for homes built between 2000-2004 that all had problems in the 2004 hurricanes.
On our 1st meeting, the client gives me 2 hand-written pages of these complaints - most were water intrusion, but also HVAC, windows/doors improperly installed, etc. He hands me this list as we are standing with the General Contractor! And he asks me to comment! He pretty much put the builder on notice that he would not accept an inferior product. He said he’s not paying over $500K for a leaky piece of $hit!