Wikipedia:Reference desk/Archives/Science/2016 September 16

= September 16 =

Best way to detect bootleg ground?
What is the best way to detect a bootleg ground?

2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 04:33, 16 September 2016 (UTC)
 * Posted from edit request to WT:RD. Nil Einne (talk) 05:35, 16 September 2016 (UTC)
 * You could measure the resistance between the case of the appliance and the neutral pin on the plug. THis should be a high resistance, of megaohms or higher. If it is only a few ohms or less, it has been directly connected.  On a three pin plug you could measure resistance between the Earth and Neutral wire.  Similiar resistances will indicate a problem as before.  The equipment used for Portable appliance testingwill also reveal this problem. Graeme Bartlett (talk) 12:43, 16 September 2016 (UTC)
 * Do not do this without basic understanding of the electrical circuits in your home. I could see a not-so-implausible chain of events where the poster borrows an ohmmeter from their neighbours, fails to disconnect the circuit breaker, and confuses neutral and phase for testing. Then, if there is indeed a bootleg ground, you have at best a fried ohmmeter.
 * Don't get me wrong, tinkering with your electrical installation is fun, and it can save you some money. But it is also a source of lethal accidents. Tigraan Click here to contact me 17:46, 16 September 2016 (UTC)
 * Also, the OP presumably is referring to the US situation, but hasn't stated so. Certain countries (New Zealand being one of them), use a 3-wire system in which the Neutral wire is connected to the Earth/Ground wire at the fuse box. Since the Earth/Ground wire is connected to the appliance case, the Neutral wire is effectively connected to the case. Contrary to the US scenario, the lack of an ohmmeter reading in this situation would indicate a fault. The article Bootleg ground correctly has a tag saying that it needs attention from an expert. Hopefully this may draw attention from an editor who has that expertise. Akld guy (talk) 19:56, 16 September 2016 (UTC)
 * It is certainly not uncommon for the neutral wire to be connected with the ground at the fuse box in the U.S. either. I suspect that may not be the current code, but what house worth having was built recently? Wnt (talk) 19:52, 17 September 2016 (UTC)
 * Current National Electrical Code (US) Article 250 specifies that (in general for utility-supplied residental and similar small-time customers) neutral connects to ground somewhere up to the main disconnect and then not again thereafter. So a house must connect them at the meter or main breaker panel, but then not at any subpanel or branch circuit. DMacks (talk) 02:35, 18 September 2016 (UTC)