Ceiling fans and continuity between conductors
From the desk of instructor Jimmie Slemp
I received a call from an electrician I know. He told me he was installing a ceiling fan, and while at the fan outlet he put his continuity tester on the hot and neutral conductors. He told me that he was reading continuity and was concerned - he believed that this reading was an indicator that there was a "short circuit" between the conductors. I asked him if this was a new circuit or if he was replacing an existing light. He said that he was replacing a light with a fan. I told him that if it worked before, it will work again.
So the question is: Why would he be reading continuity between these two conductors (hot and neutral)?
Answer: Typical branch circuits are wired in parallel. If the switch to the light was left in the ON position then he would be reading the resistance (or impedance) through any of the other loads that were connected to the circuit. According to ohms law the more loads you have in parallel the lower the total resistance. Most digital multimeters will read continuity when the resistance is below 200 – 300 ohms. BTW – the fan worked fine.