Updating Old House Wiring:
In This Article:
The 6-3G sub-feed cable is run into the main circuit breaker panel. The ground and neutral wires are connected to the ground bar. The two hot wires are connected to a 2-pole breaker.
3+ (Intermediate and Up)
About 30 Minutes
Bruce W. Maki, Editor
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This is the main breaker panel, in the basement of this old 1898 house.
This 200 Amp panel was installed two years ago during a major remodeling project. The brown material is just a 1/4" hardboard cover that is held in place by the panel's metal cover. The electrical inspector requested that we build a cover over the wires that come out of the panel.
I removed the metal cover and the home-made wiring shroud.
The coiled-up large black cable (red arrow) is the sub-feed that supplies power to the new sub-panel.
We left one large knock-out for the sub-feed cable.
But... when we ran these wires, we had placed the sub-feed (arrow 2) off to the side. This cable needs to enter the main panel at arrow 1, so we had to re-route the cable behind all those other cables.
We installed a 3/4 inch cable clamp (red arrow).
This clamp is just big enough for the 6-3G sub-feed cable.
There was just enough room on the top of the panel for this clamp. I doubt that a larger clamp would've fit.
We fished the 6-3 cable (red arrow) through the new clamp.
Then we stripped away the cable jacket and paper filler, leaving 3 conductor wires sticking out (white, red, black) and the ground wire.
We routed the ground wire around the perimeter of the panel and made a 90-degree bend so it could be attached to the ground/neutral bus bar.
We connected the ground and the neutral wires to empty slots in the bus bar.
Note: It's ONLY at the MAIN panel where the ground and neutral (white) wires are connected to the same bus bar.
At the sub-panel, the neutral bus needs to be isolated (insulated) from the metal panel box.
Then we ran the two hot wires around the left side of the panel, and made bends for the wires to turn and connect to the breaker.
We stripped about 1/2" of insulation from the ends.
We connected the red and black hot wires to a 50 Amp 2-pole circuit breaker.
This is what many people call a "220-Volt" breaker. (Actually, the voltage is no longer 220 Volts... now it's 240 Volts.)
There is 240 Volts between the two hot wires, and 120 Volts between each hot wire and neutral.
We installed the breaker in the main panel:
The first step for this Cutler-Hammer breaker is to hook the breaker over the mounting flange.
At this point the metal contacts were not yet seated on the hot bus bars.
Arrow 1 points to one of the connectors on the breaker.
Arrow 2 points to one of the hot bus bar tabs.
This connection is simply a press fit. The breaker connectors are spring-loaded and squeeze against the tab of the hot bus bar.
Before you hurt yourself, read our disclaimer.
We pushed the breaker firmly until it was seated against the hot bus bars, and the new breaker was physically aligned with the other breakers.
We removed two metal knock-outs from the cover panel.
After we double-checked all the connections, we re-installed the cover panel.
When the sub-feed cable had been connected to the sub-panel, we turned on the 50 Amp breaker.
I strongly recommend anybody who plans on doing their own electrical work to do more research besides just reading these articles. I am not an electrician and I certainly do not know everything about wiring. I could be wrong. The electrical codes in your area may be different than in my area.
While minor electrical changes and repairs may not require a permit, larger projects usually do. Consult your local Building Department (look in the "local government" section of your phone book) before making your own major electrical changes. Local electrical inspectors usually are available during their early morning hours to answer your code questions, normally free of charge. If you've done your homework, you can speak intelligently and learn about lots of valuable rules and regulations.
I highly recommend the book Wiring a House (For Pros By Pros) by Rex Cauldwell, which is available on Amazon.com.