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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7493
Experience:  Proven Professional 48 years Experience
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I live in Mississauga, Ontario and my neighborhood is

Customer Question

Hello Mike
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: Hello Pearl. I live in Mississauga, Ontario and my neighborhood is undergoing an electrical upgrade. They are installing new transformers and re-doing each electrical service. All services are underground and the original transformers were located in backyards, now being relocated to the front yards. Each house has a 100 Amp service. The new service cable is easily 1 - 2 0, while the old service cable is #4 as required by Ontario Hydro code. Why are they using such heavy gauge cable? My concern is it's a cash grab by the contractors paid for by my municipal taxes, not to mention my electrical bill. Copper is a commodity and it just seems to me that the new cable is overkill. The new cable runs are shorter then the old cable runs. Any ideas or insight into this? Thank you.
JA: How old is the system in question? And have you consulted an electrician yet?
Customer: Mid 1970's and, no I haven't.
JA: Do you plan on doing the work yourself?
Customer: The city hired contractors are doing all the work. Is anyone actually reading what i wrote here?
JA: Anything else we should know to help you best?
Customer: No
Submitted: 9 months ago.
Category: Electrical
Expert:  Kevin replied 9 months ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) If the existing underground cable was 4 AWG copper, that conductor size is rated for a 100 amp service.

2) If the new cable is 1 AWG copper, the utility most likely increased the cable size in the event a homeowner needs to upgrade the service from 100 to 150 amps. It is very common that the service lateral conductors are often increased by a minimum of 1 cable size larger than required in order to accommodate a larger amp service to the customer premise.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.


Customer: replied 9 months ago.
I didn't get anything I didn't already know. It wasn't worth the $22.00 I had to spend. The cable they installed - 000 AWG will more then double the current capacity and no one in these houses will ever expand / add that much new electrical. No one in these homes will ever pull even the old max of 100 Amps.
Expert:  Kevin replied 9 months ago.

I guess that you can predict that a homeowner will never upgrade a hot water heater to an electric tankless hot water heater that typically requires a dedicated/minimum 50 amp circuit and often more amps depending upon the water heater kW size? If this occurs, a typical 100 amp service can easily be overloaded.

If such an upgrade is installed in the future, a 100 amp service to the home via 4 AWG copper will not be able to support the existing loads along with a higher kW load from the electric H2O heater for example.

I recommend that you contact your local Public Utility Commission and utility and ask them the reason why they are increasing the feeder size? I'm sure they will provide you with a similar answer as is called being prepared for the future if a customer requires a service upgrade. 3/0 AWG Aluminum is rated for a maximum of 175 amps while 3/0 AWG copper is rated for a maximum of 225 amps.

Sorry that I did not provide you with the answer you were looking for. I will opt out of the question and place it back to the open board. Perhaps another electrical expert here can provide you with the answer that you are looking for.

Expert:  Mike G. replied 9 months ago.

Assist to Kevin.

The utility is the Authority Having Jurisdiction. They are the one spring the size of wiring on their distribution. After the meter you then have code requirements by CES. You only need to comply not complain.

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