I've reposted this topic from the Q&A forum (thank you MD for your earlier reply) to this one as it is probably more applicable here. Hopefully someone can provide an answer for me.
A question for the electricians out there. I am not a licensed electrician myself but have a good working knowledge of electronics from previous experience and study but this one has me stumped. I want to connect a 2 wire light fitting to replace an old one. The light's neutral wire is correctly connected to and has continuity with the house neutral circuit. The light hot wire has continuity with the house hot wire that goes to the light switch but the light hot wire does not go hot when power is connected to the switch. The switch and light fitting work correctly as I tested them on other lights / switches. My question is: How can the light hot wire have continuity with the switch hot wire but not go hot when power is supplied to the switch? A break in the light's hot wire would explain why it's not getting power but not why it has contunuity with the hot wire from the switch.
The wiring cannot be easily replaced or inspected as it runs through the brick / plaster walls of the house which is in a typical Khmer style 1960's concrete appartment block. Any answers would be greatly appreciated. Thank you.
Skypilot
Home Electricity Circuit
Yes. The "exit" side of the switch goes hot when the switch is turned on.
I think If there's a break (as in not all wires broken) in the wire you won't get power but continuity uses a tiny amount of power to check so will show it's ok.
Wire it directly from switch h to light. If it works you have your answer. If it doesn't there is an issue with the light.
But I'm no sparky!
Wire it directly from switch h to light. If it works you have your answer. If it doesn't there is an issue with the light.
But I'm no sparky!
pew, pew, pew, pew!
If the hot wire is shorted to ground, then it would still show continuity, but turning the switch on would just create a heating element and no power would get through to the light.
Use an ohmmeter and check to see what the resistance is from the hot wire to ground on the cable leading from the switch to the light fixture. Also check the resistance from neutral to ground on that same run. Finally, check the resistance between the neutral wire and the hot wire.
There are only 2 things that are possible with DC. Either a short or an open (or a combination of both). If you have an electronics background, check some voltages and draw up a Thevenin equivalent circuit for your black box/hidden wire under study. It should be pretty easy to figure out what is happening once you have it diagrammed.
And you can always check the wire with a battery to rule out any AC problems, although such things are very unlikely.
Use an ohmmeter and check to see what the resistance is from the hot wire to ground on the cable leading from the switch to the light fixture. Also check the resistance from neutral to ground on that same run. Finally, check the resistance between the neutral wire and the hot wire.
There are only 2 things that are possible with DC. Either a short or an open (or a combination of both). If you have an electronics background, check some voltages and draw up a Thevenin equivalent circuit for your black box/hidden wire under study. It should be pretty easy to figure out what is happening once you have it diagrammed.
And you can always check the wire with a battery to rule out any AC problems, although such things are very unlikely.
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