Electrical Newbie - Voltage Tester has "O" "L" "H" Settings - Not sure if wire is hot

splendorlex

I'm a new homeowner, and I'm ready to try to do my first significant project on my own. The exhaust fan, well, exhausted in one of our bathrooms and I'm trying to replace it.

Now, I turned off the circuit breaker that seems to govern that bathroom, as the light does not work anymore, it also governs the master bed and bath, where MOST electric seems to be off with this breaker shut off.

I bought a volt tester, have the ceiling opened and the old fan partially removed, and I exposed the black wire and hit it with my tester, but it seems to still be hot, at least I think. I bought a CE tester from the Home Depot, and it has three settings, "H" "L" and "O." What do these settings mean, and how should I use it? Maybe it was supposed to come with some kind of manual or instructions for use, but it did not. Both the "L" and "O" settings, when touched to the wire, gave a buzzing sound. The "H" setting didn't seem to do anything.

One other note is that I saw that at least one outlet in the master bath still works, as my wife's curling iron was plugged in and it was working. I'm wondering if the overall wiring is a little screwy in my new home.

rjniles

Show us a picture of the tester or at least give a model number.

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Location:
Coastal South Carolina

splendorlex

It's a Commercial Electric MS8903H.

rjniles

That is a non-contact tester but I could find the model or info on the Home Depot site.

If it is buzzing on any setting you have power. Continue shutting off other breakers til it stops. Or turn off main breaker.

__________________
Location:
Coastal South Carolina

Oso954

When I tried the HD site, it took me to a similar looking product. Gardner Bender 50-250 VAC/DC screwdriver continuity tester GVC-3206.
The CE model might be a re-brand of the GB.

I would recommend taking the tester back to HD and having them provide suitable instructions for it. If they can't, ask to return it for something that comes with instructions.

Not knowing what the settings are can be problematic. A "Yes" answer is not meaningful (no good), if you don't know what question was asked.

danpik

Those things are going to get someone killed someday. You need a good quality Test light or a volt/Ohm meter. A test light will allow you to probe a hot to ground to see if there is indeed current flowing. A good volt/ohm meter will tell you how much is there. Those non contact pens will pick up induced voltage all the time and tone as if there is real power there. I do admit to having one and using it sometimes. If it tones, Out comes the volt meter. You are most likely picking up some induced voltage on the line.

O, L, H, ---Off, Low, High maybe

DexterII

I concur. Take it back if you can, or keep it, but don't use it as a "go " or "no go" tool. I have a couple of them, and they are handy for initial trouble shooting, but do yourself a huge favor and use a meter.

jeffnc

That's a CAT II rating, which I think is good enough for 120V lines, but I'd take it back and get a CAT III which is the minimum recommended I'm told. I have this Klein which is actually CAT IV but it's worked perfectly for me within the confines of what these things can do.

http://tinyurl.com/a9j3rwf

BigJimmy

My guess is since it probably emits a tone to indicate the presence of voltage, O, L, H=Off, Low (volume), High (volume).

As someone else suggested, I'd get a different tester. If nothing else, a solenoid tester (often referred to as a "wiggy") at least applies a load to the circuit thus eliminating the chance of reading a false presence of voltage. DVM's are good but can under certain circumstances provide odd results to the inexperienced given their high input impedance. A test light or tester that actually applies a load is the best.

I read years ago where non-contact testers could fail to indicate the presence of voltage depending on the type of shoes/boots that the person was wearing, whether they were on a ladder (and what type of ladder they were using), etc. I've got a Klein n/c tester that I use only as a basic indicator but always have my Amprobe VM on hand to make sure.

Jimmy

__________________
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diystephen

Never use a non-contact tester as a definitive measure of testing voltage. It's always considered an "accessory" troubleshooting tool, and never a primary means of verifying power. Take it back and get yourself a multimeter.

dmxtothemax

[/ATTACH]These types of testers are not definative !
And should not be rellied on definatively !
They can and do give false indications !
Please use a better type of tester,
such as a anologue meter
Attachment 64078
Do not use digital, as it too can give false indications !
Attachment 64079
Or use a test lamp instead

fltdek

Outlets in bathrooms must be on a separate circuit, which is why the curling iron is indicating "on", where as lighting and exhaust fans can be tied into a number of different rooms/lights