Occasionally still live in the oldest stock, usually feeding a single circuit nobody has traced. It has no ground, it degrades where buried in insulation, and most insurers will not write a policy on it.

This is most common in homes built before about 1940. Pre-war construction — galvanized supply, cast iron drains, cloth-wrapped wiring, ungrounded circuits.

Related

• Federal Pacific or Zinsco panel
• Two-prong outlets throughout the house
• Cloth-covered cable visible in the attic or basement
• Fuse panel, or a 60 amp service
• Fuse larger than the wire it protects
• Ceiling fan mounted to a standard light box
• No GFCI protection anywhere in the house
• Breakers or fuses that are not labeled

Back to Electrical.

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Written by Jaylan Jones. I Like To Fix earns a referral fee when a call connects to a contractor. See our business-model disclosure.