Minimum   Minnesota VA/FHA

Electrical   Service  Requirements

By Douglas Pencille

Minimum Service Requirements | Adding Loads To A 60 Amp. Service

Requirements For Electrical Outlets/Fixtures


Much confusion appears to exist as to how much is really enough, as far as electrical service requirements in a home are concerned.   When performing inspections on homes with older electrcal systems I am often confronted with questions like: Will the existing 60 amp. main service be adequate? - or - What about this older "knob & tube" wiring with frayed insulation. . .will it need to be replaced?, etc. 

One rule of thumb here is, "When in doubt, consult with a qualified licensed electrical contractor."  The following section provides a summary in several key areas:


Minimum Service Requirements

  1. All single-family dwellings with less than a 60 amp. 115-230 volt 3-wire service will require a 100 amp. 115-230 volt service, however:
  2. An existing 60 amp. 115-230 volt service may remain if: 
  1. It is in good condition.
  2. It is not overloaded.
  3. If major electrical appliances are to be added or if additional circuits or greater electrical loads are needed, Section 220-31 of the NEC (National Electric Code) "Optional Calculation for Additional Loads in Existing One-Family Dwelling Occupancies" shall be used.
  1. Internal wiring and outlets shall conform to:
  1. One 15 amp. branch circuit with balanced load for every 575 sq. ft. of habitable floor area.
  2. At least one duplex receptacle on a separate 20 amp. kitchen appliance circuit.
  3. At least one duplex receptacle on a separate 20 amp. laundry circuit.
  4. Minimum numbers of receptacle outlets shall be as required by the local Housing Maintenance Code.
  5. Bathrooms shall have at least one receptacle.  This receptacle may be in a wall light if readlily accessible.
  6. All hazardous wiring and all disconnected wiring shall be removed.   This includes wiring to and in garages and other accessory buildings.
  1. All applicable local codes and ordinances, when more stringent, shall apply.



Adding Loads To An Existing 60 amp. Service In

A Single-Family Residence

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.

The 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 calculation worksheet."



Electrical Outlet Requirements

  1. 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.
  2. 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.  
  3. 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.
  4. Every public hall, water closet compartment, bathroom, laundry room, and furnace room shall contain at least one supplied electric light fixture.
  5. 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 installed.
  6. The electrical service and all wiring shall be maintained in good condition, and used in a safe manner.
  7. The Director of Inspections may order any hazardous electrical installation removed.




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