||There has been much confusion and discussion
relative to how much additional load is permitted to be added to an existing 60 amp.
service in an existing single-family dwelling.
National Electric Code gives two methods for making this determination, both of which are
acceptable. One is to calculate the load as per Section 220-4 "Calculation of
Feeder Loads." The other method is relatively simple and was new in the 1971
National Electric Code Section 220-31 "Optional Calculation for Additional Loads in
Existing One-Family Dwelling Occupancy." Section 220-31 has merit and is
valuable as a quick check method to determine if additional load can be added to an
existing 60 amp. service.
NOTE: "I have found
that some electrical contractors are not actually performing the load calculations when
asked to certify an electrical service for a residence. On at least three occasions, I
have inspected houses where the electrical service was certified only two or three years
previously, but failed when the house was re-sold because a different electrical
contractor was called in who actually crunched the numbers! In each situation, the
seller then had to foot the entire bill to upgrade an electrical service they had been
told was adequate. Needless to say, they were NOT happy campers! To
protect yourself, BE SURE that an actual load calculation is performed, not just a cursory
walk through the house. Also, you should ask for a copy of the actual load
Electrical Outlet Requirements
- In all existing dwellings now or hereafter supplied with
electrical service, every habitable room with 120 sq. ft. or less of habitable
floor space shall be provided with two separate floor or wall type electric convenience
outlets, and an additional electric convenience outlet shall be required for each
additional 80 sq. ft. or fraction thereof of habitable floor space.
- Required outlets shall, insofar as possible, be spaced equal
distances apart. Outlet spacing shall not exceed the distance required
to connect them to a lamp with a six foot cord extending in either direction, or a maximum
of twelve feet. Kitchens and rooms with kitchen areas shall have one
convenience outlet in addition to the number herein required for other habitable rooms.
- One ceiling type electric light fixture or one wall type
electric light fixture controlled by a remote switch may be supplied in lieu of one
required electric convenience outlet in each habitable room.
- Every public hall, water closet compartment,
bathroom, laundry room, and furnace room shall contain at least one supplied electric
- All electric outlets and fixtures shall be installed,
maintained, and energized by a source of electrical power in a manner complying with the
City Electrical Code applicable now, or at the time such outlets or wiring were or are
- The electrical service and all wiring shall be maintained in
good condition, and used in a safe manner.
- The Director of Inspections may order any hazardous
electrical installation removed.