PORTABLE GENERATORS
Portable generators are being used increasingly by homeowners to provide back-up or stand-by power.
Generators and associated equipment (i.e. transfer switches, etc.) shall be installed by a registered
electrical worker or contractor under a valid installation permit.
Portable generators and associated equipment shall be approved and shall carry the mark of a recognized
certification agency.
Recessed male receptacles (flanged inlets) shall be used as an interface to the generator at the building
being fed, and shall be of weatherproof construction. A portable cord set of the hard usage type with one
male and one female end shall be used shall be sized to correspond with the maximum output of the
generator receptacle. The cord set shall not be permanently fastened to anything as it is intended that the
cord be stored after use.
Neutral Connections
It is crucial that the entire electrical system is properly grounded and meets all code requirements.
Generators are available with the neutral bonded to the frame or without (floating neutral). This
information will be visible on the generator, usually on a sticker or a tag.
The following installation practices shall be used:
When the Neutral of the generator is bonded to the frame of the generator:
If the generator has its neutral bonded to the frame, the neutral should also be grounded to a grounding
electrode and the transfer switch should have an extra pole to switch the neutral. Switching the neutral
will ensure that at any given time the neutral is only grounded at one point (either the main switch or the
generator).
When the Neutral of the generator is not bonded to the frame of the generator (Floating Neutral )
If the generator has a floating neutral, it should not be grounded to a grounding electrode nor should it be
switched in the transfer switch. The generator frame is bonded to ground as a result of the “equipment
bonding” requirements of the Code (Rules 10-400 to 10-414) and the neutral connection to the electrode
is maintained at the main service via a solid neutral connection in the transfer switch.
Not every situation is the same
Because of the variety of emergency and standby power systems, it is not always feasible to provide fixed
recommended practices. Each installation should be evaluated and designed to satisfy specific load,
customer and code requirements. Furthermore, in situations where it may be necessary to remove bonding
screws or jumpers in the service switch or at the generator, manufacturer’s instructions shall be strictly
adhered to and documentation from the manufacturer provided to the inspection department prior to
making any alterations.
Call us
If you have a question or require clarification on any of the foregoing, please call the inspections office at
873-7399 and ask to speak with one of our inspectors.