Bang! Large flash / bang at voltmeter tips.

[Tasty]

Hi all,

Just had quite a fright & must say I'm pretty annoyed with myself.

I've just tested the ends of a wire to check if it was live (using a fluke voltmeter) and had a massive flash and bang at the points of the probes). I'm annoyed because I should have isolated the circuit and terminated the wire in a block rather than testing wire as it was found (it was left as you'd find twin and earth if had just been cut, not stripped).

Could you guys help me with what the bang was so I can learn properly from this mistake? (I'd have said it was the very loose contact I had between probes and wires but I'd appreciate any thoughts and correction on this). The rcd and mcb blew but everything seems ok now. I've isolated the wire at the switched fused spur unit the cable leads to & will fully isolate before terminating the wire properly now.

Thanks in advance,

Stu

 

[Knobhead]

We all learn as we go along in life.
Sometimes the lesson hurts.
You’re not the first and I doubt you’ll be the last.
You’ll not fall for it again though will you!

I’m lucky I walked away from a 15KV 150VA to earth shock!
To be honest I limped away! I was blown flat on my back. It ******* hurt! What saved me was a timber floor and a set of timber step ladders!
To hell with rubber mats they’re only good to 1KV

 

[RogertheBodger]

Can't imagine what that must feel like

 

[SirKit Breaker]

Its happened to the best of us as Tony has testified, and i am no different. fortunately i have never experienced a shock at any sort of KV, and i bet there aren't many who have lived to tell the tale when they have.

I have not had an electric shock now for nearly 2 years. Its easy to avoid. Dont assume its dead, make sure it is dead. Treat every cable as though it is live until you know it isnt. Its not hard to do, we just get lazy and complacent, so dont feel bad about it. The main thing is that you have learn't a valuable lesson.

Cheers...Howard

 

[mechelec]

no but you do have very long probes

 

[mechelec]

All I’ll say is it’s your own fault!
Try testing live at 11KV, no room for forgiveness what so ever!

you do have very long probes though !!

 

[mechelec]

We have all done somthing similar at some point. The important thing is to learn from it. Saying that most people have probably done it more than once. lol

 

[Dazza1976]

I must admit, i have done this myself before, so i will be careful in future.

Just to add though, someone mentioned about stripping back the cable and putting in a connector block before testing to see if its live or not, but you wouldnt want to go stripping back cable and terminating until you know that it is dead, hence the reason he probably tested that way in the first place, so what would you suggest ? use a volt stick ? As you cant assume a cable is dead just because everything is switched off at the board ?

 

[rmc86uk]

Agreed with above. How can you isolate the circuit if you do not know what the circuit is hence why you are testing for voltage in the first place.

Sent from my HTC Desire using Tapatalk

 

[rryles]

Switch off at main supply and then test with voltstick? (Oh and still assume it could be live!)

 

[sparky3366]

In the late 80's, a college tech in the electrical department somehow managed to blow the blue phase on the main busbar on the incomer. Turns out he went over red & blue phases with a little multi-meter. All the college had to be sent home...
This is the same college where a lecturer insisted on calling ohms 'barrats' as in barrat homes cos he thought it was funny. One guy failed his 236 because he kept putting barrats in his exam paper instead of ohms.
The same lecturer was sacked for an issue of ordering cable & fittings from the wholesaler and ending up with washers, kettles etc instead, which he promptly sold on...alledgedly

 

[ian.settle1]

Switch off at main supply and then test with voltstick? (Oh and still assume it could be live!)

In the immortal words of John McEnroe


You can not be serious!

 

[rryles]

I was completely serious. This was as a precursor to stripping the offending cable and terminating into a terminal block so that you can then correctly identify and isolate.

What else would you suggest? Test the cut end of the cable with probes? Isn't that where the OPs original problem started?

 

[Dazza1976]

Switch off at main supply and then test with voltstick? (Oh and still assume it could be live!)

Im not sure if he was actually saying do this, or if he was questioning my previous post, i think there may be some misunderstanding.

In my post i was asking how you would test if a cable like this was live, as previous posts suggested stripping back the cable and terminating in a connector block to test, but i pointed out that you wouldnt really want to do it this way if the cable is live, thats why i asked about using a volt stick, coz i know of a time where my ex college mate got a nasty bolt, where he went to work on a circuit, the main switch on the consumer unit was off, but it turned out there was another small 1 way consumer unit that was hidden.

 

[Dazza1976]

Sorry just read your reply rryles, and i do agree with what you are saying, it will be interesting to hear what the others say on this matter.

 

[ian.settle1]

For one a voltstick in the eyes of the HSE is not an approved voltage indicator.