Proper Method to Ground an Old Electrical Fuse Box

It is an NEC safety requirement that your house circuitry be grounded.

The National Electric Code requires grounding on your service panel, but if you have an older house, it is possible that neither the fuse box nor the individual circuit elements are grounded. Such electrical systems are hazardous by today’s standards. Grounding prevents a fixture from becoming live and giving you a shock, and also prevents fires. If it is impractical to retrofit your circuitry, you can at least ground your fuse box and provide a path to ground for circuit elements through the neutral wire.

Step 1 – Pound a ground rod at least 8 feet into the earth near the fuse box and within 5 feet of the point where your metal water pipes exit the house. This rod should be made of unpainted metal. If it is made of ferrous material, it should be 5/8 inches in diameter. If it is made of nonferrous material, like copper, it can be 1/2 inch in diameter.

Step 2 – Attach ground clamps to the water pipes and the ground rod. Run a length of 10-gauge ground wire between them and connect it to the clamps with a screwdriver.

Step 3 – Connect another length of 10-gauge wire to the clamp on the ground rod and run it to the fuse box. Use the shortest route possible, drilling small holes in the house siding and the floorboards if necessary.

Step 4 – Turn the power off to the fuse box. Call the electric company or an electrician to do this. Don’t just remove the main fuse, because this will not de-energize the hot bus and it will remain capable of giving you a fatal shock.

Step 5 – Loosen one of the clamps on the side of the fuse box holding incoming circuit wires. Feed the ground wire through and pull it until you have 12 to 16 inches of slack. Tighten the clamp to hold the wires securely.

Step 6 – Connect the ground wire to the metal body of the fuse box. You can do this by drilling a hole in the back of the box and inserting a ground screw. Wrap the wire around the screw and tighten it. Leave a tail on the end of the wire that will reach the neutral bus.

Step 7 – Install a ground bus if you have circuit cables with a ground wire or plan on installing these. Drill holes in the back of the fuse box. Screw on the bus and connect the ground wire to the main lug.

Step 8 – Connect the ground to the neutral bus. If you attached it to a screw, run the end to the neutral bus and connect it to an available lug. If you installed a ground bus bar, bond the ground bus to the neutral either by connecting a copper bonding plate or a piece of 10-gauge ground wire to both bars.

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