light is shocking me!

Patryk_Rebisz

Patryk_Rebisz

Veteran
My 1.2 HMI has given a zap to two different crew members on two different shoots. Anyone knows best way to trouble shoot it? I have no problems of opening the fixture and seeing is anything is loose ut wanted to know if anyone can offer some guidelines. It's LTM 1.2 PAR if it matters.
 
Patryk

Never a good thing and more than dangerous. Make sure your crew has dry socks! Somewhere in the fixture, the case has become hot and your crew has become the easiest path to ground. Surprising that the fixture still works or the power supply hasn't been damaged. Look for loose wiring touching the case of the fixture. If nothing is found, you may need to have the power supply tested for faults.

Grant
 
If it is the fixture and not the ballast, it should be pretty simple to see the problem. Look at the wires going from the cable to the lamp and check for any signs that a wire is somehow in contact with anything other than the lamp. Maybe heat has made the insulation brittle and cracked. Check the socket to see if it is cracked or otherwise compromised.

It sounds like two problems. The case should be grounded such that any bare wire inside the case that is touching it will cause a short and blow a breaker. This is a basic safety requirement. It may not have this if it is a very old fixture.
 
Duncan Craig said:
If I owned kit that was electrocuting my crew I wouldn't have waited for the second electrocution before I asked the internet what to do about it.
Click to expand...

Well, yeah. Because if someone had been electrocuted they would be dead. An electrocution, by most definitions*, is fatal. If they're not dead, then they just received an electric shock.

*Miriam Webster:
Electrocute verb: to kill by electric shock

transitive verb: to kill or severely injure by electric shock

I don't know if "severely injure" is a recent addition to the definition or not. From my news background(before the current overly casual/overly conversational/less clinical style of reporting) , the term "electrocute"/"electrocuted"/"electrocution" was only used when the electric shock resulted in a fatality or death.
 
I don't want to judge, I don't know the circumstances but Duncan Craig has a point. And semantics about shock or electrocution won't change that.

If your gear gives you an electrical shock it is broken and you should fix it immediately I'd think.

Especially when you offer your gear for rent, as OP's tagline suggests. A shocked crewmember is bad enough but you don't want dead customers don't you ?

Dead customers are bad for business.
 
Last edited:
Electrocution is terminal. No exceptions.

Actually the usual look for loose wires approach can fail in an HMI because while touching the case and getting a belt usually means you got a 110 or 230V shock, with HMIs there is also the potential (sorry) for a much higher voltage shock when the lamp strikes up - a few thousand volts to start the discharge cycle. This has the capability to jump and find paths that ordinary 110/230 cannot do.

If you have some electrical knowledge there are things to check before you do anything else - if you don't have the knowledge, unplug it and do not use it till you find somebody competent.

Check with a meter that there is a direct continuity between the metal case and the earth pin in the mains connector. This is there for safety, and should conduct any stray voltage down to ground where trips will flip, or fuses blow. If there is no ground connection to the case, it can run at mains voltage and work fine! Till, of course you touch it. It is possible that a live tingly case is NOT full mains, but low current leakage - but you cannot test this unless you understand what is going on. If you have a meter, you can see if the case is live - as in put it on a ac setting and stick the problem between ground and case. If it reads your mains voltage - then unless you know what's going on - step back, unplug and find somebody else - do NOT use it.
 
You must log in or register to reply here.
Back
Top