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Dave-Denver 08-24-2008 11:27 AM

Is Power cheaper with 200A Service?
One of the guys who gave me bid for a bunch of basement work including a new service panel (my old Murry panel is 30 years old) said my electrical bills would be lower if I moved up to a 200A service rather than staying with a 150A that I now have. This makes no sence to me! FYI, Load calc - 135A


Pudge565 08-24-2008 11:29 AM

No electric won't be cheaper he is just trying to get more money out of you.

Dave-Denver 08-24-2008 11:34 AM

Pudge, thanks for killer fast response! And for the good info too!

ccarlisle 08-24-2008 11:35 AM

Perhaps he's referring to some electric appliances working more efficiently at 200A (like heaters) and therefore capable of giving the same output at lesser consumption. Depends...

daxinarian 08-24-2008 11:36 AM

If he is dishonest about that, what else was he dishonest about. And if he legitemetly believes that it will save you money, he is an idiot, do you really want a liar or an idiot working on your electricity?

micromind 08-24-2008 01:01 PM

The cost per kilowatthour (usage) is exactly the same whether it's a 100 amp, 200 amp, or 1000amp residential service.

The cost is different for commercial/industrial services, but not residential.


buletbob 08-24-2008 02:59 PM

That's a first, I have herd that three phase machinery was cheaper/ efficient to operate then single phase. others Please chime in if i,m not correct. BOB.

wire_twister 08-24-2008 04:48 PM

I have always understood that 3 phase equipment is more efficient/cheaper to operate, but the size of the service has nothing to do with the cost to operate.

ccarlisle 08-24-2008 05:31 PM

I'm with wire twister; up here, most of our electricity is generated by a system of dams and reservoirs i.e hydroelectricity if you will, and most homes have 200A service panels to contend with electric heating via baseboards in most homes. No other heating sources in those cases. So radiant heat is a big thing; they push the larger 2500W wall heaters supplied by 240V circuits since it is more efficient to heat with them vs say tw0 1250W heaters on single 120V circuits.

That is what I was saying earlier. Thus in this case a 200 A panel would be cheaper to run - installation costs etc aside.

220/221 08-24-2008 05:32 PM


I have herd that three phase machinery was cheaper/ efficient to operate then single phase. others Please chime in if i,m not correct.
Not really true.

In some cases like large motors, the individual phases will draw fewer amps allowing for smaller wire size and less heat.

In other cases like residential AC units, the single phase units are actually MORE efficient with higher SEER ratings.

micromind 08-24-2008 06:41 PM

In theory, a 3 phase motor producing the same HP as a single phase one will consume 83% of the power to do so. This assumes identical design, except for the way the stator is wound. As stated above, A/C compressors are sometimes an exception. They are designed differently, so efficiency is different.

What I meant about rates is (around here anyway) is the cost per kilowatthour. Rates per kilowatthour are different for different types of services. Residential is one rate, (single or 3 phase, any size service), small commercial is another, (single or 3 phase, I believe the upper limit here is 500KW), large commercial is yet another.

It doesn't matter much if a specific load is run from a 100 amp panel or a 1000 amp panel, it is still going to consume pretty close to the same kilowatthours over any given time, and thus cost the same to operate it from either panel, provided the rate per kilowatthour is the same.

Hopefully, this clears it up a bit.


ccarlisle 08-24-2008 07:25 PM


Following your example of the 3-phase motor giving the same output and requiring 83% of the power, wouldn't you say a given baseboard heater was more economical to run on 240V than on 120V - to heat the same?

I think that is the gist of the OP contractors statement...

micromind 08-24-2008 08:20 PM

Suppose the baseboard heaters were 1000 watt. Either one would consume 1000 watts, and if operated for 1 hour would consume 1 kilowatthour regardless of voltage.

The advantage the 240 volt unit has over the 120 one is the current is less, meaning smaller wile can be used. You pay for kilowatthours, not amps, thus the cost of operation is the same at either voltage.


Dave-Denver 08-24-2008 08:40 PM


I get (mostly) the 220v / 110v and the single phase vs. other stuff.

But for running common household stuff like lightbulbs, the frig etc... having a 150A vs. a 200a service panel makes no difference at all on utility bills for us in the real world.


ccarlisle 08-25-2008 06:23 AM


I understand. However my question was: for the same btu output, is it cheaper to run a 1000W heater via 120V or via 240V... :whistling2:

Denver Dave: Yup; no difference in the cost of running a light bulb via 120V or 240V.

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