Confused with power requirements

Old 07-27-12, 05:38 PM
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Confused with power requirements

I have had two licensed electric contractors quote a similar job. One says I need more power to back sub panel and the other says no.
Have 100 amp main in house feeding a 100 amp panel in detached mother in law suite which is run off a 60 amp breaker to feed the apt.

I want to install split AC unit, washer/dryer and stove, microwave in the apt. Do I need more service to apt in rear? Do I need more service running to main house to feed apt?
Old 07-27-12, 06:00 PM
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Welcome to the forums! Did either of the contractors do a load calculation on the residence? They should have run one on your part, the apartment and combined. I am certain if they had the conclusion would have been the 100 amp panel you have would be insufficient.
Do you have a washer/dryer, stove, AC in your part of the house?? I am sure you do. What you are wanting to do is draw power from an already taxed set up to service basically another house. It would be best to separately meter the apartment and let it have it's own panel.
Old 07-27-12, 06:57 PM
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Might cost less to put in a separate meter. The 100 amp panel would probably be okay with its own meter but a 60 amp feed is just to small.
Old 07-27-12, 11:30 PM
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I agree a demand Load cal should be done. To add: Not all jurisdictions will allow two services on one property.
Old 07-28-12, 09:31 AM
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The NEC requires a 100A minimum service on a dwelling.
Old 07-28-12, 01:39 PM
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Is the sub-panel in a stucture seperate from the structure where the Service Panel is located ?.

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