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Inspecting Ungrounded Branch Circuits

Many times home inspectors are told that the “electric service was updated.” Automatically people think that the house was rewired. In reality the main service, and possibly sub-panels were replaced and updated with modern circuit breakers. However many two wire ungrounded branch circuits remain. Often times knob & tube wiring is still being used. As can be seen in the picture, many of the branch circuits are older 2 conductor and do not have a ground. Many of these are cloth covered. Some are metal sheathed or BX / AC cable. Using the metal sheath is not considered a ground, however may show as one if the metal components are bonded. This was addressed in another newsletter. Even though the receptacles have been changed to 3 prong receptacles, they are not grounded. We can tell by looking in the electric panel just how many branch circuits are not grounded. When I am inspecting the electric panel, I inform my clients that the service panel has been upgraded, however many branch circuits are not grounded. I explain to them that a ground protects you. The circuit will still work, however it is not considered safe without a proper ground. My clients always ask me; “what do you recommend”. I inform them that all circuits should be grounded. Grounds protect people and appliances / devices, however there are things they can do to provide some degree of protection for ungrounded branch circuits. Of course the best and most expensive thing they could do is to rewire the ungrounded branch circuits with grounded branch circuits. Here is some more information and some other ways you can advise your client:

  •  Install a Ground Fault Circuit Interrupter receptacle or circuit breaker at the beginning of the circuit. It should be labeled; “No Equipment Ground”
  • A tamper resistant GFCI would be a better option
  • Knob & Tube wiring can nuisance trip a GFCI because of shared neutrals
  • GFCI test buttons apply current between the hot and neutral. GFCI testers you may use, apply current between the hot and equipment ground. So if there is no equipment ground, the tester will not trip the GFCI receptacle
  • The receptacle can be individually grounded if connected to the equipment ground rod or on a metal water pipe within 5 feet of entering the house
  • Installing a Combination Arc Fault Circuit Breaker or receptacle may also provide protection from older wiring that could be prone to the type of failure these devices are able to detect
  • A Combination Arc Fault / Ground Fault dual function circuit breaker with a  tamper resistant receptacle might be the best option if rewiring the entire branch circuit is not possible
  • It is important to note that fire resistant materials are required for anything combustible

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