I have a 1921 bungalow. Wiring is generally updated, but some artifacts from a while ago exist.
My bathroom had a single fixture light at the end of a circuit. The power source fed in from another room with a box with multiple wires in it. The power came into the bathroom to a box with a single-pole switch. From the switch the power ran to the overhead light. Black to switch, black from switch to light, whites joined.
Here’s the question: Why does the breaker trip if I join the source feed wires in the switch box. (i.e. I connect the black and white wires from the source where they used to control the switch and overhead light)? It does not trip if I cap each wire individually.
This is probably a dumb question but I figured why not ask. Thanks in advance.
By the way: I tested the source: 120 volts, and it doesn’t trip when I use the multi-meter.
Replies
Because that shorts hot and neutral together.
Mark is correct,
your breaker better trip pretty fast if you tie the black and white wires together - in a typical house, you likely are getting 200 to even upwards of 1000 amps short circuit current flowing.
No question is a dumb question, but it does indicate that you need to go to the library and learn a little more before randomly tying wires together!
I'm 100% for DIY anything, with a knowledge base; however, you have a high probability of doing something that could harm your family if you don't find out a little more about electricity and home wiring.
thanks. i've already called in someone to help out (licesned electrical guy). I figure you all could answer this quickly though.Follow up dumb question: why does having a light there not make it trip-- doesn't the hot flow though the light and back thorugh the neutal? why does having something in between solve this issue?Promise, this is the last dumb newbie Q. (for today)
The light fixture has resistance which reduces the current flow. A 60 Watt bulb only draws 0.5A (60W / 120V = 0.5A).
thanks.