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



## rjniles (Feb 5, 2007)

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


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## splendorlex (Jan 20, 2013)

It's a Commercial Electric MS8903H.


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## rjniles (Feb 5, 2007)

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.


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## Oso954 (Jun 23, 2012)

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.


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## danpik (Sep 11, 2011)

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


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## DexterII (Jul 14, 2010)

danpik said:


> 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.


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.


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## jeffnc (Apr 1, 2011)

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*


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## BigJimmy (Jun 30, 2006)

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 (Nov 23, 2012)

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.


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## dmxtothemax (Oct 26, 2010)

[/ATTACH]


splendorlex said:


> 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.
> 
> ...


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
View attachment 64078

Do not use digital, as it too can give false indications !
View attachment 64079

Or use a test lamp instead


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## fltdek (Oct 14, 2009)

splendorlex said:


> 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.


 
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


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## garella (Nov 22, 2014)

*How the Commercial Electric MS8903H works*

H=high sensitivity (detects up to a foot or so away)
L=low sensitivity (detects up to 2-3 inches away)
O=off

If it buzzes: there is electricity nearby. 
If it doesn't buzz, then *you don't know for sure*.

It makes sense to test it first near a known live circuit so you know it's basically working. 

As other have said, this thing is useful in some limited circumstances, but to know for sure you need a circuit tester.

Just remember: This device can show that there *is* electricity. It cannot show that there *isn't* electricity. 

There are two LR44 batteries inside. Lift the green clip a little and slide the end off to get to them.

Turn it off when done so they don't die on you.


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## Jake. (Sep 29, 2014)

garella said:


> H=high sensitivity (detects up to a foot or so away)
> L=low sensitivity (detects up to 2-3 inches away)
> O=off



Welcome to the forum! :thumbup:

That was an almost 2 year old post. I checked the OP's stat's and that was the last time she/he was even on the site. 

You get what you pay for in a NC voltage detector though too. This is the one I use and I swear buy it.


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## r0ckstarr (Jan 8, 2013)

Jake. said:


> That was an almost 2 year old post. I checked the OP's stat's and that was the last time she/he was even on the site.


2yrs old. I learned something new from it.

I've been using this one for basic at home electrical things.

http://www.homedepot.com/p/Klein-To...=REC-_-PIPHorizontal1_rr-_-NA-_-203391692-_-N


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## del schisler (Aug 22, 2010)

splendorlex said:


> 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.
> 
> ...


you are messing with maybe your life, take that back and get a analoge volt ohm meter , they have them, set it to at least 120 AC volt and not ohm scale, now measure , than you will know but i bet that is not on the outlets side for voltage? , other than this let a pro do it ?? i been in electric for 60 or more yrs it can do you in if you arn't carefull


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