Testing line voltage sockets for residual voltage/current.

[sean k]

So I got caught out the other night when I plugged my stuff into the monitor chain. I shoulda guessed when I plugged it all in and got a twinge off the power plug itself as I plugged it into the multi socket but it wasn't much more than a twinge so I didn't click. Then my stuff wouldn't fire up and I pulled the output from the mixer to beep the signal to the amp and got a fairly large bolt from the earth on the lead.Oww! "bugger"

It was'nt that big but it was enough to realise there was voltage sitting on the earth so I unplugged and found another socket that wasn't on the monitors.

I plug in two wall voltage plugs, one to the amp which is earthed, and the other to the 9V box, which is earthed but the 9V outs are floating, so I have virtually no loops in my system except for maybe the FX loop on the mixer (I'm not sure and will have to look to check).

Once I was into another socket I was fine but it made me think about ways to test any multi sockets for residual voltage/current without resorting to a store bought handheld that electricians use to test new wiring in houses. I think maybe the man had an earth lift on his monitors so they were floating and the power amps were at a higher voltage than my stuff so I got the difference through my body but then again it was most probably 230VAC because it was as big as one I got last week by inadvertantly touching the active on a socket.

Can anyone suggest a simple tester I could hook up to a spare wall plug to test sockets and what actually happens to do so.

[biggy boy]

In North America we use one of these.
You may be able to find a 230 volt equivalent.
they are small and inexpensive.

The yellow guy at the bottom left.

http://images.google.com/imgres?imgurl=http://quick220.com/pic_TEST001thumb.JPG&imgrefurl=http://quick220.com/&usg=__kG5Nn35Rwqpr-tL4azWcfTi-few=&h=100&w=61&sz=16&hl=en&start=66&um=1&tbnid=yrNJ45vBT-VWdM:&tbnh=82&tbnw=50&prev=/images%3Fq%3D230%2Bvolt%2Boutlet%2Btester%26ndsp%3D18%26hl%3Den%26rls%3Dcom.microsoft:*:IE-SearchBox%26rlz%3D1I7ADBF_en%26sa%3DN%26start%3D54%26um%3D1

[sean k]

Thanks Biggy, I'll have a look but I'd still prefer making something so I can understand whats going on.

[R.G.]

Thanks Biggy, I'll have a look but I'd still prefer making something so I can understand whats going on.

As regards the outlet tester, it may be better to buy two, and cut one open to understand them. I don't know about you country, but these things cost between US$2.00 and US$5.00. You'll spend more time (=money) trying to build something and doing a second rate job (on a safety and reliabilty basis) as well as probably more money. I can't imagine being able to buy the parts for one of these for less than $2 in postage to get them here.

At the price, there is almost certain to not be much inside, possibly just three neon bubs and three resistors. But the custom molded plastic case and non jury-rigged plug in setup is a real advantage.

Just as a thought, I view one of these outlet testers as one of those life-tools, something no thinking person would be without. They don't wear out, and you'll likely need it again.

[biggy boy]

Even the Hydro (electrical) inspector uses one to test my work.
To make sure the outlets are wired correctly, I'm an Electrician by trade.

[sean k]

I just checked in '07 catalogue of the place I buy from and they've got basically the same thing for 24.90 which is no where near double the price for the exchange rate. I suppose thats the accepted thing here in New Zealand at the bottom of the world, were far away and theres only 4 million of us so we pay a premium for what the 1st world, up in the top half, gets for almost nothing. If it was 6 or even 10 bucks I wouldn't think twice but theres something innately wrong with spending 24 dollars on... I guess it's just a NZ thing. Just checked the '09 catalogue and they are up to 29.90. Okay its a safety thing but more than ten times more expensive than you guys pay. Can you imagine paying 18 dollars for these things? Even if it took me an hour or two to design and build and I spent ten dollars on materials I'd feel better than paying 30.00 over the counter. I'm not cheap... I'm just aware about where my money goes to.