Using a Multimeter - Testing voltage in house?

Question

Could someone explain to me how to use a multimeter to check if a wire is live? It is for a house, so I am assuming its 120volts. I'm installing a ceiling fan and the wiring in the room is kind of weird. I don't want to just assume its off because I flipped the breaker in that room. (P.S. I don't want to flip the main breaker because I have some vital electrical devices running in the house). http://cgi.ebay.com/COMMERCIAL-ELECTRIC-MULTIMETER-HDM350-NEW-LEADS-MANUAL_W0QQitemZ180004507617QQihZ008QQcategoryZ25412QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting <~~~~Picture of Multimeter I am using

Thanks!

Answer 1

Dont use a live circuit tester, they are cheap and useless. Its good you purchased a meter, it would have been better if you purchased a Fluke meter. Anyhow, dont follow the advice of sticking one wire to the junction box......terrible advice. I looked at the photo of your meter, you need to turn the dial to AC volts, I cant see the options in the picture but around dial there should be an option for AC and DC volts. Install the leads into the Com and V of the meter, you should only have 3 wires supplying power to the fan, black, white and green. Put one of the meter leads to black and the other to white, if the breaker is off you should read zero volts, check black to green and white to green as well ( some people may think that is rediculous but you never know who wired your house, may have been a crack head). Turn the breaker back on and do the same checks, you should read volts at this time if you do then you know you have found the correct breaker. Test your meter in an electrical outlet that you know works before using it on the wiring that you are unsure of.

Answer 2

All these answers are are good and will work in most cases but there can be some exceptions. I would be especially cautious about only measuring to the box. If this is an older house (or it looks wierd) then it may be that the person who installed it may not have grounded the box (as is now required).

The live circuit tester (wand thing) is a good idea as it looks for a voltage relative to your body (what you are really interesed in). Using that should cover all the bases.

Answer 3

For the best answers, search on this site https://shorturl.im/axw5u

batteries made in many diffrent technology, like normal ones, alkalines, rechargables (ni-cd,ni-mh,li-ion) and so on. they cant be testet completely with a multimeter if you have no knowledge in electronics. but at least buying a multimeter is better idea than a battery tester! here are more details for non rechargable batteries: a battery shows a higher than its real voltage when you measure it without a load, battery voltage must be measured when its driving a load (a device like a clock etc...). in this case bettery voltage should be near to that specefied on it, so its ok. if battery is completely run out it has a lower than named voltage on terminals altought without any load, so if you read a 1.5v battery as 1v or something near it (like up to 1.2v) its relatively empty. for a 9v empty battery you may read 7v. these batteries can't power the device anymore. test of new batteries are easy, eg. for a 1.5v you must read 1.55v or a little higher (because its new and thers no load), 9.5v for a 9v battery and so on... this voltage will drop a little when you supply it to the device and get to the battery's named voltage. so you have to measure the battery voltage when a device powered by it. good luck

Answer 4

I would read the manual and then test yourself by trying to read the voltage on a battery. I really recommend you buy a live circuit detector. They are about the size of a pencil and usually cost $9 to $12. When you put them close to a live wire or outlet, they buzz and/or light up. They have saved me from shock many times. If you are going to do your own wiring work, even simple stuff, these detectors are a great safety device.

Answer 5

It will have no effect which one is which as you have one hot and one basic, the multi meter does not know and does not give it a second thought. it ought to enlist voltage on the off chance that it is available.

Test your meter in an electrical outlet that you know works before utilizing it on the wiring that you are uncertain of.

I cannot see the choices in the photo yet around dial there ought to be a possibility for AC and DC volts. I know about sparenparts here all industrial products are available

Answer 6

RE:
Using a Multimeter - Testing voltage in house?
Could someone explain to me how to use a multimeter to check if a wire is live? It is for a house, so I am assuming its 120volts. I'm installing a ceiling fan and the wiring in the room is kind of weird. I don't want to just assume its off because I flipped the breaker in that room. ...

Answer 7

there are two ways to verify the power is not on where you want to work.
first the multi meter has a black and a red lead. in common household current the two wires represent a circut. take a lead and put it on a wire, it will make no difference which one is which as you have one hot and one common, the multi meter does not know and does not care. it should register voltage if it is present.
second, you are probably attaching the fan to an existing light fixture. before you start, turn off the breaker you suspect supplies the power to that fixture, then turn it on. if it comes on you guessed wrong on your breaker. if it does not come on you have what you are looking for.

Answer 8

Commercial Electric Mas830b

Answer 9

Play it safe and turn off the main circuit breaker, after powering down any delicate electrical equipment you have. After all, the power could go out any time due to storms, power outages, brownouts, etc. Anything that is truly incapable of withstanding the loss of power should always by protected with a battery-backup UPS, very inexpensive these days at any office supply store.

Answer 10

take one lead and put it on the metal box the wires are in. Put the other lead on each of the wires one at a time. see if the meter registers any voltage