Lack of Electrical Safety

church

Active Member
An interesting topic. It is always difficult to comment on the practices allowed from one country to another when electrical regulations vary so much. I am from the UK and I know live in Canada I am a licenced professional engineer in both countries and both countries are very different in what they allow - with good reasons that reflect practice and also history of how power genmeration and distribution has evolved. Not surprisingly Canada shares many similarities to the US - but not all US practice applies in Canada. In fact not all Canadian practice applies in all Canadian provinces. However all countries have one thing in common: the regulations are becoming increasingly more stringent as we seek to protect people from the inherent danger of electricity.

Just a long winded way of saying just because something doesn't match how we normally do it - doesn't make it wrong but it is definitely interesting.
 

Logos

Well-Known Member
Can you clarify one thing for me? So in the theatre you can use piggy back plugs. I thought they had been banned in Australia or is this only for domestic
use. I used to work for an Australian retail electronics and we couldn't get piggy back extension leads because they didn't sell them in Australia.
Later
Cutlunch

The situation now is that you can purchase for domestic use moulded plug piggy back extension cords rated at 10amps. These are used extensively in the theatre. Unfortunately they are almost always white.
If you are a licensed electrician or a company working in an industry where piggy backs are useful you can purchase piggy back plugs but only in lots of 100. They come with blind pins so they cannot be taken apart afterwards. I have seen the blind pins replaced with screws but anyone inspecting and testing cables are supposed to immediately condemn and destroy cables like that.
I'm a little horrified by the picture that Hughsie started this thread with. I guess that if they were PAR 56 300W and the dimmer was rated at 5K it would be electrically safe sort of but mechanically stacking that number of piggy backs is at the very least stupid. That would probably break the pins or damage the dimmer.
 
Last edited:

dj_illusions

Active Member
the traditional form of 110v par can splitter in australia where you would have two female 110v sockets into one male 240v socket is now illegal. the split now must be made inside a sealed enclosure such as a plasic jiffy box and attached to a bar, and from what i understand the notion of a 110v par split in australia is trying to be phased out. some manufacturing companies have remedied this problem by adding a 110v plug to certain dimmer models while others have made a straight through 110v-240v adaptor and told the rack it is a 110v can as oppose to using a splitter on the bar.

in australia when a new standard is made, anything new after the enforcement date must comply with the standard however if it was acquired previous you are allowed to continue using it until it becomes insafe.

there for in the instance of a par split if you have the older style they can still be used until unsafe or fail a routine electrical test, the same applies for the 'piggy' back plugs that are not sealed, if they have a screw or pin or do not have insulated neutral and active pins they can still be used until unsafe.

in the venue i work in, in melbourne we do a test and tag every 6 months of all lighting equipment and extension leads/splits to ensure everything is safe with no problems.

hopefully this helps clarify a few concerns the guys in the states may have!
 

derekleffew

Resident Curmudgeon
Senior Team
Premium Member
Hughesie89 is your original picture kind of like ten of these plugged together? Perfectly safe, in the right hands. A fire trap, in the wrong hands!
 
Last edited:

DAE

Member
Hello, I'm Don from Perth, Western Australia.
The piggy back plugs you see in the picture are not plugged in to any dimmer or lead so are not drawing any current, Some venues have a strange practice of plugging all of their unused patch leads into each other as a housekeeping thing to keep them tidy. This is usually done in venues where the tails lie on the floor instead of being installed at the correct height where they will just clear the floor so they hang straight and clear of each other.

They should have their patch panel rebuilt to have the patch leads hang correctly as it saves you time when patching a show and leads lying on the floor are not good practice.

I design my shows with one fitting per bar socket so if you need to repatch it can be done at the patch panel. This means in small venues with low wattage lights such as the Par38 100watt, you can have 24 per 2400 watt dimmer channel. Once I have more then two piggy backs in a channel I will used a short extension lead to go from the dimmer socket to the piggy back patch leads and tie the multiple piggy back leads up to support them. If I have done this on a show I unplug those leads after the show so incompetent people don't think they can do that to any situation.

ps where do newcomers say hello, I can't find it.
 

Logos

Well-Known Member
Hello, I'm Don from Perth, Western Australia.
The piggy back plugs you see in the picture are not plugged in to any dimmer or lead so are not drawing any current ....
True on second look they are not plugged in.
ps where do newcomers say hello, I can't find it.
On the forums front page top section is called General with about 5 or 6 threads. The bottom one is the New Member Board.
Welcome aboard.
 

JD

Well-Known Member
"Originally Posted by DAE
Hello, I'm Don from Perth, Western Australia."

Now, there's some confusion in the making! DAE is the name of my company! ;)

Welcome aboard!
 

Hughesie

Well-Known Member
they were connected to a dimmer, i pulled them out during a bump out (load out) and took a photo, and they turned out to be each 500w groundrows, dangorous stuff if you ask me :(
 

David Ashton

Well-Known Member
Not really a safety issue at all, if you did plug in a heap of cans you would simply blow the fuse/breaker, the piggy back plug is about the only good electrical idea Australia has to give the world, our 3 phase plugs are an embarrassment.
 

Hughesie

Well-Known Member
yeah but at the school i work at the new lighting techs love to push everything up then bring the grand master down and push it all the way up, and they see nothing wrong with it, but then wonder why so many of their globes die, that was on a LSC wallpac dimmer

proxy.php


all other circuits were loaded also
 

David Ashton

Well-Known Member
This is most likely a neutral shifting issue putting more voltage on one phase on the inrush surge, no way should bringing up all your lights on a fader blow lamps.If you had 5kw plugged in to a 2.4 socket and it worked there are serious deficiencies in your system.
 
Last edited:

Logos

Well-Known Member
Yeah, if you're talking about standard c-form 3 phase they aren't much different from UK plugs.
 

David Ashton

Well-Known Member
Australian 3 phase plugs have a neutral pin which has half the cross sectional area of the active pins and the neutral current on a dimmer between 30-60% is over 120% of the full load current/phase which means that a 32a plug will run nearly 40a down the neutral pin which is half the size, which means that neutral pins burn out regularly, CEE plugs have live and neutral pins the same size and the neutral makes contact before the actives and are therefore safer.
 

Logos

Well-Known Member
Yes of course you're right sorry. Most of the stuff I use lately is in permanent rig and I don't unplug it.
 

Hughesie

Well-Known Member
you forgot that, it's not just one flash, it's on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off,on, off. at about the speed you are reading it
 

David Ashton

Well-Known Member
flashing at high speed should be less stressful as the filaments stay warm and have lower inrush current.Run an experiment with a new lamp on a continuous chase, I think you will find it runs for days with no problem.
 

dj_illusions

Active Member
I have only seen a burnt neutral pin on a 3phase plug once which was caused when someone removed a 32amp plug form a socket at FULL load, apart from that I have seen general wear and tear but never a situation you are talking about.

These plugs are used widely not just in our industry, in others where a much more constant power draw is used. I am sure if there was a 'problem' as you say with the plugs they would have changed by now but as far as I am aware they have followed the same design principle for the last 20+ years...

most common fault you find is someone shaving the additional guiding pins off a 40 and 50 amp plug to make it fit into a 32 amp socket, that is probably one of the biggest design faults.
 

David Ashton

Well-Known Member
If you've only seen one burnt out neutral pin you must have lived a very sheltered life, I have several in the shed along with a burnt out minipack where the fire started in the neutral.I would change six a year around the schools I mainly work in, but as you point out the other big problem with them is that if they are not plugged in properly or unplugged live then it is pot luck as to whether the 3 phase pins or the neutral pin is making contact, unlike the CEE plugs which make neutral contact before the actives.
 

dj_illusions

Active Member
all the newer clipsal plugs coming out now have a longer neutral and earth pin or shorter live pins to ensure they make clean contact first.

i see alot of 3phase around this time of year doing lots of festivals etc. and will hardly ever see burnt pins, as i said most common thing I see is shaved guiding pins.

An imporvement should be not to the plug, but the socket in making a reed switch or similar that will not allow the socket to go live regardless of the switch position unless the secure screw on ring has made contact to ensure the plug is in properly as many people just put them in, i have done it before aswell without screwing in the ring.

but compared to alot of the connectors around the world i think ours is one of the best systems with the least confusion aswell.
 

Users who are viewing this thread