Ask Me Help Desk - Might scrap 200amp upgrade and go with a bigger 100amp panel

Hey all!

Reading all the posts about 200amp panels and the costs is making my head hurt along with my wallet. I think I will just have the existing 100 swapped out for a larger panel... say a 30/30 100amp (or are there larger ones? ). I live in a 77+ year old house with some older knob&tube wiring and a few window AC circuit upgrades, that I didn't do, but that's about it.

Does that sound reasonable? Should I just get a decent sized 100amp panel or save up for the 200 in the long run? The panel issue is slowing my remodel.

Also would it be safer in the interim to replace the existing ungrounded outlets with GFCI's until they are replaced?

Sizing a service is not done by guessing, or how many circuits that are needed.Thou I do not show how to do the calculations for connected load here, if you give me the total square foot of livable space, not including unfinished basement, garage, attic, crawlspaces, and list all major electric appliances, type of heat & hot water, AC, I can do the sizing for you, the accuracy will be relative to the information you provide.

If you like, you can review the calcs in the latest NEC code edition at the library, don't bother looking for it on the web, codes are extremely copyright protected.

If the ungrounded outlets are three wire, then they should not be there, and yes they need to be GFI protected. This can be done by using a GFI breaker to protect the entire circuit, or use one GFI receptacle at the beginning of the circuit which will protect all the outlets downstream, and use the labels provided "No Equipment Ground" on all the outlets.

Knowing how K&T wiring is done, it is rare to find wiring going from outlet to outlet as all the splicing is done behind walls and ceilings. A breaker may be your best bet for K&T wiring.

Quote:

Originally Posted by tkrussell

Sizing a service is not done by guessing, or how many circuits that are needed.Thou I do not show how to do the calculations for connected load here, if you give me the total square foot of livable space, not including unfinished basement, garage, attic, crawlspaces, and list all major electric appliances, type of heat & hot water, AC, I can do the sizing for you, the accuracy will be relative to the information you provide.

If you like, you can review the calcs in the latest NEC code edition at the library, don't bother looking for it on the web, codes are extremely copyright protected.

If the ungrounded outlets are three wire, then they should not be there, and yes they need to be GFI protected. This can be done by using a GFI breaker to protect the entire circuit, or use one GFI receptacle at the beginning of the circuit which will protect all the outlets downstream, and use the labels provided "No Equipment Ground" on all the outlets.

Knowing how K&T wiring is done, it is rare to find wiring going from outlet to outlet as all the splicing is done behind walls and ceilings. A breaker may be your best bet for K&T wiring.

I did a rudimentary calculation and I even padded a few watts here and there and ended up with about 60amps total but I am sure you can get more exact so here are my numbers.

1200sqft living space not including the unfinished basement.

No diswasher but I figured in 1200 watts for future.
No disposal but I figured in 900-1000 for that.
Fridge is listed at 4.5 amps
Hot water is gas so no power there.
Two window ac units, one at 550 watts and the other is unknown but larger... its sealed in the one window and already is wired to a 15A/230V circuit.
I don't have a range at the moment but we are going gas on that one.
I figured 5000W for the dryer... the existing is a little older but works great.
Heater is hot water radiator at 2.5amps... at least that's what it says on the motor.

I also figured in on one GFCI front & back yard and a few for the basement... about 1000 watts including lighting... I use those smaller wattage bulbs.

There are a few 3 wire outlets that are ungrounded running off the existing K&T wiring... dont know why but I intend to change that. All the K&T circuits are on breakers.

It is going to be a headache!

Several of your guesstimates were dead on.

Using the optional method, AC larger than heating:
3600w 1200 sf @3 watts/sf Lighting load
3000w 2 appliance circuits
1500w 1 laundry circuit
1200w 1 DW
8000w 1 range
5000w 1 dryer
22300w Total
@40% = 8920 demand + 2000w AC @100%= 10920 total connected watts/240 volts=45.5 Amps

Min size service allowed is 100 Amps derated at 80% allows 80 amps.

100 Amp service with a 30 circuit panel is fine, with ampacity to spare.

Now doesn't not guessing feel better?

Yes I know what you mean on the rewire, plan it all out, do one room at a time, before you know it, done.

And I actually misread your list, you have a gas range, so you save the 8KW I entered for the range, and gain more ampacity.

Quote:

Originally Posted by tkrussell

And I actually misread your list, you have a gas range, so you save the 8KW I entered for the range, and gain more ampacity.

Yes sir!

I will still install the range outlet though for "future" considerations... not necessarily mine but another owner.

I appreciate your help in all of this!

Quote:

Originally Posted by Cerberus

I will still install the range outlet though for "future" considerations...not necessarily mine but another owner.

Interesting tidbit of info - according to the electrical code in Ontario, any oven location that does not have a built-in oven requires a 220V oven outlet, regardless of whether you're using a gas stove. Probably because it would really suck to buy a house, move your stove in, then find out that there's no outlet there.

I really should get a copy of the CEC, I think it will be interesting reading, yes I like reading electric code, weird huh?

I do understand the electric code is modified by Providence also, which must make it even more difficult.

I think it would help me when I have customers complain about the strictness of the NEC here in the USA. My opinion is that once the NEC is thoroughly understood, it can be very friendly and lenient and forgiving.

I actually think it is a great idea to figure in and allow for the range, as Cerberus has done, even though he does not need to, and go figure, someone has already done that in Ontario by requiring this to be mandatory because they realize that people have preferences, and will change the gas unit to electric.

Man, I will have a rough time trying to shove that down some Americans throats, I get crap for trying to install outlets every 12 feet, and putting outlets 5-10 feet from spas, why the need for transfer switches when they use generators, and on and on. They all think it is a huge conspiracy and that I am part of the machine, and once they learn I work for the union, well I better keep my back to the wall.

You Go Canada!

Hey Tk,

I had the electricians out today... and they quoted me a price of $2500+ from their price book for a 100amp panel swap with a ground rob install. I almost passed out... luckily the tech lives two blocks from me and will do it for 700$ on the side... no inspection is necessary because nothing is really changing.

I would expect 2500 for a 200amp upgrade... is that a little steep for a 100?

Quote:

Originally Posted by tkrussell

I really should get a copy of the CEC, I think it will be interesting reading, yes I like reading electric code, weird huh?!

Why, just read all of your buddy's old posts, he'll tell you all about it. Or do you only like reading correct electrical code?

ROTFLMAO... you kill me... I needed that!