100 amp service on my rental

3471 Views 49 Replies 20 Participants Last post by JimmyJones99, Mar 29, 2020

JimmyJones99

Discussion Starter · Mar 10, 2020

Hey guys i just bought a rental house and it has a 100 amp service. Just put in a laundry room and Electrician says service is too small and that we need a 200 amp service. But it passed inspection and it is working but he claims it will start tripping breakers soon... but it hasn't.

Currently has a 10kw furnace, normal electric range, clothes dryer, 40 gallon water heater and then lights and plugs etc. 1100 square feet.

Looking for a 2nd opinion about electrical loads. Thanks!!

1 - 20 of 50 Posts

Wiredindallas

· #2 · Mar 10, 2020

I agree it needs 200 amps. The inspector just looked for the wiring to be safely installed. Code only requires 100 amps., but with electric heat, etc. you need more.

Reactions: 1

Kevin_Essiambre

· #3 · Mar 10, 2020

Yes, you should have a 200 amp service installed.

10kw is 42 amps +/-
40 gallon hot water tank is 12.5 amps (usually. Can be more. This is based on 3kw elements).

We are already at 54.5 amps of items that run whenever they want.

I believe this would push you over 100 amps with a load calculation but I don't feel like doing one.

Electric range, electric dryer, general use receptacles, lighting, etc. will push a load calculation pretty high.

Sent from my new phone. Autocorrect may have changed stuff.

Reactions: 2

CodeMatters

· #4 · Mar 10, 2020

I'd be disinclined to make this expensive change until/unless
the main starts tripping. There's no safety issue, just inconvenience.

Not easy to find tenants with half a brain (....I've had a dozen
tenants...) but if you do have reasonable tenant(s), you can
encourage them NOT to run oven and dryer at the same time.
That's likely all it'll take to not trip the main.

If other owners want to give up a year or 2's profit to unnecessary
upgrades, go for it.

Reactions: 2

Missouri Bound

· #5 · Mar 10, 2020

You definitely need a 200 amp service.
But the old comedy show Green Acres had a solution:
You put numbers on all the appliances and make sure the total is less than your limit.

Reactions: 2

Old Thomas

· #6 · Mar 10, 2020 (Edited)

I would be cheap and wait since it hasn’t happened and if it does it is not unsafe. If it happens once tell them not to run the dryer and stove at the same time. I would not spend the money until I had to, then I would see if I could upgrade the entrance wire and put a 150A main breaker in the existing panel.

Reactions: 3

JimmyJones99

Discussion Starter · #7 · Mar 10, 2020

Is tripping the main breaker what will happen now? The lady who lives there has never had one breaker ever trip and she is concerned after Electrician told us that.

My one hesitation is i had a similar house 20 years ago but it had baseboard heat through out so probably less amps than the furnace maybe?

Wiredindallas

· #8 · Mar 11, 2020

As I and others have said, 200 amp is best, but it is not unsafe as is. It is surprising how much 100 amps will operate because everything does not stay on all at once. This is called the demand factor. The only thing is to be sure the panel is not one of the brand's that are not safe such as FPE or Zinsco.

Reactions: 2

CodeMatters

· #9 · Mar 11, 2020

Actually, let's see if I can still do an Ontario load calc. @Kevin Essiambre can check my work

100 sq ft = 102 m^2

90m^2 = 5000W
next 90 m^2 =1000W
heat =10000W
range =6000W
dryer (at 25%) =1200W
water heater (at 25%) = 750W

That comes to = 23950W
making current (/240) = 99.79A lol That strike anyone else as funny

So barring errors or larger appliances, a 100A service meets code in Ontario.
Unlikely to trip main.

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Reactions: 3

CodeMatters

· #10 · Mar 11, 2020

JimmyJones99 said:
Is tripping the main breaker what will happen now? The lady who lives there has never had one breaker ever trip and she is concerned after Electrician told us that.

My one hesitation is i had a similar house 20 years ago but it had baseboard heat through out so probably less amps than the furnace maybe?

That's right, no safety concern, only issue is nuisance of (unlikely) main
breaker tripping.
Why does the tenant know what the electrician said? If he talked to her,
HE SHOULDN'T HAVE! If you told her. WHY?

Reactions: 4

JimmyJones99

Discussion Starter · #11 · Mar 11, 2020

CodeMatters said:
That's right, no safety concern, only issue is nuisance of (unlikely) main
breaker tripping.
Why does the tenant know what the electrician said? If he talked to her,
HE SHOULDN'T HAVE! If you told her. WHY?

Because she lives there and was present when me and electrician were there. I went over with her later what may happen with the main and how it was no concern at all... but she is nervous about power.

MTN REMODEL LLC

· #12 · Mar 11, 2020 (Edited)

JimmyJones99 said:
Is tripping the main breaker what will happen now? The lady who lives there has never had one breaker ever trip and she is concerned after Electrician told us that.

My one hesitation is i had a similar house 20 years ago but it had baseboard heat through out so probably less amps than the furnace maybe?

I'm with everyone above as to waiting to see if there is a tripping problem.

Load calcs are ultimately just a subjective ESTIMATE of expected usage.....

If I read correctly you have a single tenent in there, that not unsurprising has had no problem.

Now, if you have to re-rent sometime to a family of four with two Tesla's and is an industrial welder out of your garage.....then better reassess your service.

With regard to your lady tenents concern,,,, remind her of the old adage..."Never ask a barber if you need a haircut":wink2::smile:

Good luck....

EDIT: With the caveat of WIREDDALLAS, if its a Federal Pacific or Zinsco, I'd personnally get rid of it. They scare me....

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JimmyJones99

Discussion Starter · #13 · Mar 11, 2020

CodeMatters said:
Actually, let's see if I can still do an Ontario load calc. @Kevin Essiambre can check my work

100 sq ft = 102 m^2

90m^2 = 5000W
next 90 m^2 =1000W
heat =10000W
range =6000W
dryer (at 25%) =1200W
water heater (at 25%) = 750W

That comes to = 23950W
making current (/240) = 99.79A lol That strike anyone else as funny

So barring errors or larger appliances, a 100A service meets code in Ontario.
Unlikely to trip main.

That is funny! She told me that Easter, May long weekend and Christmas would be the only times when all burners and oven used at once as well possibly dryer in use when kids are home.

MTN REMODEL LLC

· #14 · Mar 11, 2020

JimmyJones99 said:
Is tripping the main breaker what will happen now? The lady who lives there has never had one breaker ever trip and she is concerned after Electrician told us that.

My one hesitation is i had a similar house 20 years ago but it had baseboard heat through out so probably less amps than the furnace maybe?

I'm with everyone above as to waiting to see if there is a tripping problem.

Load calcs are ultimately just a subjective ESTIMATE of expected usage.....

If I read correctly you have a single tenent in there, that not unsurprising has had no problem.

Now, if you have to re-rent sometime to a family of four with two Tesla's and is an industrial welder out of your garage.....then better reassess your service.

With regard to your lady tenents concern,,,, remind her of the old adage..."Never ask a barber if you need a haircut":wink2::smile:

Good luck....

Reactions: 1

Let it Snow

· #15 · Mar 11, 2020

10KW furnace
No Heat Pump?
5KW Dryer
4KW Water Heater
8KW Range
2KW sq footage
29KW total
29,000 watts /240 volts = 120 Amps
Some will say that it's not all on at the same time. That's mostly true until Thanksgiving or Christmas with a house full of people.
Change it now to 200 amp.

CodeMatters

· #16 · Mar 11, 2020

Let it Snow said:
10KW furnace
No Heat Pump?
5KW Dryer
4KW Water Heater
8KW Range
2KW sq footage
29KW total
29,000 watts /240 volts = 120 Amps
Some will say that it's not all on at the same time. That's mostly true until Thanksgiving or Christmas with a house full of people.
Change it now to 200 amp.

Are you saying that's how a NEC load calc is done?
Or just making up your own demand factors?

Reactions: 1

JimmyJones99

Discussion Starter · #17 · Mar 11, 2020

Let it Snow said:
10KW furnace
No Heat Pump?
5KW Dryer
4KW Water Heater
8KW Range
2KW sq footage
29KW total
29,000 watts /240 volts = 120 Amps
Some will say that it's not all on at the same time. That's mostly true until Thanksgiving or Christmas with a house full of people.
Change it now to 200 amp.

Easter long weekend it is happening, all the kids home and big dinner, deserts etc. I am nervous!

MTN REMODEL LLC

· #18 · Mar 11, 2020

JimmyJones99 said:
Easter long weekend it is happening, all the kids home and big dinner, deserts etc. I am nervous!

Jimmy...if it helps you sleep at night... change it out. (I sleep better considering normal risks of the protection provided by my OCP device)

No one knows the issues at Easter if a rabbit is under cooked because of an oven blackout...:wink2::biggrin2:

Kevin_Essiambre

· #19 · Mar 11, 2020

CodeMatters said:
Actually, let's see if I can still do an Ontario load calc. @Kevin Essiambre can check my work

100 sq ft = 102 m^2

90m^2 = 5000W
next 90 m^2 =1000W
heat =10000W
range =6000W
dryer (at 25%) =1200W
water heater (at 25%) = 750W

That comes to = 23950W
making current (/240) = 99.79A lol That strike anyone else as funny

So barring errors or larger appliances, a 100A service meets code in Ontario.
Unlikely to trip main.

Yup, that is accurate.

Now, what if the service is done with #2 aluminium? Table 39 states #2 is only good for a calculated load of 95 amps. I hope its #3 copper or larger aluminum.

Of course, it is existing...

I knew the load calc would come in pretty on the line. I hope they don't add anything! Any supplemental heat would push us over the limit.

OP stated in another post that the tenant may use all of the range and possibly the dryer over Easter weekend. So there is the possibility of the range using it's full rated capacity... but if that causes the main to trip, I would be more concerned about the insulation or the location of the thermostat! Cooking/baking a ton of stuff produces heat. The furnace shouldn't have to run while doing all the cooking/baking... at least, in a perfect world.

To OP, it's fine the way it is for now (at least by CodeMatter's and I opinion, and according to our code). If the main does start tripping, you can look into getting 3 quotes to upgrade the service.

I redact what I said in my earlier post saying to upgrade. I'd wait now.

Sent from my new phone. Autocorrect may have changed stuff.

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Reactions: 2

Old Thomas

· #20 · Mar 11, 2020

So is there a 150 amp main breaker available for your panel? If so, you might need a heavier drop wire and a breaker, a fraction of the cost of replacing everything.

Reactions: 1

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