It is MEA’s recommendation that the transfer switch be installed by a licensed electrician for safety and proper application.
On the next page are two alternative diagrams showing arrangements for wiring in your transfer switch.
Alternative one (1) requires that the transfer switch must be the same size as the
main disconnect located adjacent to the meter. This transfer switch arrangement is capable of
carrying all existing loads under normal conditions. This means that the only limiting factor on the
amount of electrical equipment to run at the same time under emergency conditions is the size of
the generator installed. Under emergency conditions, the homeowner may need to turn off all circuit
breakers in the distribution panel except for those circuits that feed the emergency load unless the
generator is large enough to carry the entire load.
Alternative two (2) allows selected electrical loads to be separated out of the main
distribution panel in the house and wired into a sub-distribution panel. This limitation of this alternative
is that the entire house load cannot be totally incorporated into the standby generator circuit.
When incorporating a standby generator system into your electrical system, it is necessary to make
a decision on what electrical loads are to be run in times of power outages. The main loads considered
necessary to run are: furnace fan and pump (fuel oil or gas furnaces), water well pump,
freezer and refrigerator. Normally, if all this equipment has ¼ HP motors, we can assume a 1250
watt generator, at minimum, should handle this load. Many of these motors run on 240 volt (particularly
the well pump), and therefore a 120/240 volt generator should be purchased. A larger size
generator may be required depending on the size of the well motor. If a customer decides to purchase
a smaller size generator, it may be necessary to also alternate the operation of the main
loads.
By consulting with your electrician, an electrical plan can be made which will determine what equipment
may be run at the same time. This will be the basis on which the size of generator (rated in
wattage) is determined.