Two services

Has anyone out there ever encountered, or heard of, two distinct services to the same property (both services derive from different transformers)? One service enters the back of the house from the alley while the other is to the front of the house on the street side. All of the bonding/grounding of both systems utilize the same plumbing system----no ground rods for either system. One is a 60 amp service dating to the 30’s, while the other is a 100 amp service dating to the 60’s.

Yes usually to two apartments . If it is a single home now they should go to a single service much cheaper here in Canada.

Roy Cooke

To clarify both of these services go to the same house on the property.


**230.2 Number of Services. **A building or other structure served shall be supplied by only one service unless permitted in 230.2(A) through (D).

No way. That should have never been allowed to happen. At least in any place that had any codes in place.

Multiple services are common, but are connected to a single drop or lateral. This is common as Roy stated, for apartments and multi-family’s.

Unless there is a firewall, creating two “sepatate” parts of the same structure; then two distinct services, fed from different sources, in different locations on the structure, is not legal now and I would think it never was.

It could be that the building was converted to a duplex to rent out a portion of the house back in the 60’s and years later a new owner came along and converted it back to a single family dwelling.

The home is listed as a “legal” duplex but it is actually more like a mother-in-law as there is free communication between the upper and lower unit without firewall/fire-door separation. And as stated earlier both systems appear to share grounding/bonding.

Here are some of the exceptions that may or may not apply. . .

**(B) Special Occupancies. **By special permission, additional services shall be permitted for the following:
(1) Multiple-occupancy buildings where there is no available space for service equipment accessible to all occupants, or
(2) A single building or other structure sufficiently large to make two or more services necessary

If it is permitted as a duplex there is no problem with 2 services. Around here that may actually make the house more valuable since they limit duplex zoning now and you can’t split a single family home.

Greg, is there no problem with the mixing of grounding/bonding?

I can’t see a problem with sharing the ground electrode system. You would not want to see any regrounding or combining of the neutral after the service disconnects tho.
In an old area with all metal plumbing the whole city shares a grounding electrode system.

Thanks Greg

How many main panels and separate sevices might you expect to see in a 25.000 square foot home? Commercial kitchen… toys pulling lots of power, etc. Maybe three 200 amp services?

I did a 20K sq ft that had a single, 1600 amp - three phase service. . .

Commercial kitchen, two elevators and a vehicle lift (4 vehicle capacity).

Jeff, I am curious what you charged for that inspection?

A bundle. . . :wink: