What causes copper wires to turn green or black in an electric panel?.Is it alright to just put wire nuts on the end of unused or abandoned NM-cable or wiring?.What is the maximum spacing requirement for securing NM-cable (nonmetallic-sheathed cable)?.Can service condutors be installed in the same raceway/conduit with feeder or branch circuit conductors?.Here’s links to a collection of our other blog posts about ELECTRICAL WIRING:

Go to our articles What is a service conductor?and What is a feeder conductor? for the difference between the two. These sizes for service conductors also apply to feeder conductors. The aluminum wire used for service cables and wiring for larger-amperage circuits in a home is multi-strand and a different metal composition that the solid aluminum wiring used during the early 1970s, that was later banned as a fire hazard.įor the sizing of copper service entrance cables, see our blog post What are typical copper service entrance wire/cable sizes for the electrical service to a house? Also, the grey or black gooey stuff you will see around the aluminum wire lug connections is a required anti-oxidant paste. Electricians and experienced inspectors can tell at a glance if the service cable size is correct most of the time.Īluminum wire sizes are usually one notch larger than copper for the same service rating. But not all cables are clearly marked and sometimes the lettering strip is just not visible. Wire size may be marked on the side of the cable, followed by the letters “AWG,” like in the photo below. The correct sizing of the neutral depends on doing a calculation of the “unbalanced load,” which is an estimate of the amount of 120-volt current usage. The neutral wire is often one or two sizes smaller than the two hots. An often-used rule-of-thumb is to jump up one wire size for each 100 feet of a long run. Wire sizes are AWG (American Wire Gauge), and adjustments may be necessary due to temperature rating or length of wire run. Here’s a listing of the standard aluminum service entrance wire sizes for residential 3-wire single-phase service.

Service entrance wire size for 100 amp