Mixing hard and dimmed power in socapex

[revbobuk]

a universally recognised colour code,

And DON'T YOU DARE remind us of the old mnemonic for that code... http://www.blue-room.org.uk/public/style_emoticons/default/dry.gif

 

Ha! I remember my old boss telling me that one many years ago. I've been sitting here for the last few minutes trying (and failing) to remember what the P stood for (who exactly was it who went without?!) .... http://www.blue-room.org.uk/public/style_emoticons/default/unsure.gif

 

 

Don't forget that a teacher got sacked for using that mnemonic (back in 2011) to teach the resistor colour code to a young engineering student. Some bits of the past do have a sell-by date!

[Charlotte_R]

Some good food for thought there!

I think that I'll probably keep mixing hot and dimmed power, but I might start colour coding the sockets by power type (and continue colour coding the socas).

The reason I don't use the resistor colour code is because brown and red are very similar in the dark, and I rarely get past 6 bars!

 

[Simon Lewis]

Just out of interest, does anyone actually use the (hopefully obsolete) 8 circuit fan in and fan out for standard 19 pin soca?

It had the horrific possibility that if someone plugged an eight way fan in at one end and a six way fan out at the other the cases of anything plugged into ways 1 and 3 would be live at full mains voltage. (with mains neutral connected to the cases of circuits 2 and 4).

 

Clive - there's some other issues, too:

 

A certain hoist controller has L1, L2 and L3 on socapex pins 16, 17 & 18. If a lighting socapex cable were inadvertently plugged into the controller, there would be a live case (each on a different phase) on circuits 4, 5 & 6. If the fixtures were on a truss, hopefully it'd short pretty quickly. If it happened to be a few floor cans, that could be very nasty.

If the lighting socapex happened to have pins 13 to 18 commoned, there would be an L1, L2, L3 dead short.

If the lighting socapex happened to bond the shell from pins 16, 17 or 18, the soca shell could be live...

This pinout chart from Kinesys shows some of the possible problems if gear from different manufacturers is mixed...

Of course, if the audio guys decide to use soca at their amp racks, and a speaker soca gets plugged into a dimmer, there's even more scope for letting out the smoke...

[indyld]

It's funny that one day I'm telling the young uns in the warehouse that we used to use shorting plugs and 15A cable for 110v stuff and we snicker about how much more sensible and foolproof our systems are these days.

 

Right while prepping motor looms made of back to back Soca and slinging all manner of Soca fan ins and outs on the same job. Along with an array of specialist jumpers.

 

And 3 pin XLR for both some of the DMX system and Comms.

 

We actually still rely on a lot of knowledge at the hands of the end user.

 

Regarding the OP, the common question these days is do we stick the handful of dimmers left in the system down the hot power multis? Yup, pretty often. The odd Source 4 still gamely doing its little job among the banks of waggly coloury things gets shoved on a spare way.

 

It wasn't that long ago that way 6 was reserved for movers. Now it's often the the place for the one dimmer circuit. Haha

 

:-)

[bigclive]

A certain hoist controller has L1, L2 and L3 on socapex pins 16, 17 & 18. If a lighting socapex cable were inadvertently plugged into the controller, there would be a live case (each on a different phase) on circuits 4, 5 & 6. If the fixtures were on a truss, hopefully it'd short pretty quickly. If it happened to be a few floor cans, that could be very nasty.

 

Argh! I could imagine someone picking up two unlit lights on a wooden stage not realising that their body had become live with one phase when they grabbed the first one, until they grabbed the second. That would be horrific! It would result in instant high hand to hand current flow and rapid burning. Hopefully they might get a tingle from the first light to stop them if there was enough of a ground path, but on a dry wooden stage that might not happen.

 

This is one of those areas that the event industry really needs to get its act together. Especially given the widespread use of inexperienced casual crew to do electrical tasks.

[Jivemaster]

Soca is used largely for power distribution to lanterns, BUT the noise dept use it for speakers, and other people use it for other things. Be sure that your (hired) soca is wired to the standard that you expect, and that only your soca is connected to your kit at either end. Once you've done that dimmed or hard power can easily be handled on the same soca.

 

Be very wary of anyone with eight core fan in/outs it's not usually found but it doesn't mix with 6 circuit soca systems.

[david.elsbury]

Weiland (Harting) is quite common over here wired as a 5 circuit loom. Earth to the shell and pins 1-10 alternate L/N for each circuit.

 

It might not be amazing in terms of safety but always passes PAT so no issues.

 

A company I used to work for decided (as they were Australian owned) to use a different standard of wiring as a 4 circuit loom- to avoid having to use the shell as the only earth.

 

Great idea until someone subhired some local Weiland to add to stock for a big show and something got cross connected .... I think it tripped breakers rather than killing someone which is a definite plus.

 

The safer option would have been to use soco and avoid having two competing standards of Weiland out there... but hindsight is always 20:20!

[Simon Lewis]

If there's an agreed way of wiring Soca type 19 pin connectors (or 16 pin Harting) that would be a good start...

 

Whilst most lengths of socapex do wire pin to pin for pins 1-18, some common pins 13-18 (although apparently that's not allowed in the US?) some use pin 19 as an extra earth and some earth the shell by suitable means. That latter "safety measure" could give a live shell in the case of the hoist controller mentioned above.

 

It wouldn't be so bad if safe operation could be observed as long as the correct gear was connected at either end of the socapex cable, but with that particular hoist controller, you have to know the wiring of the socapex cable before connection...

[Andrew C]

some common pins 13-18 (although apparently that's not allowed in the US?) some use pin 19 as an extra earth and some earth the shell by suitable means.

...and if you don't, I'd like a quiet word with you... I've had a belt from a faulty soca shell, fortunately on the stage, rather than above it.

[Charlotte_R]

Of course, if the audio guys decide to use soca at their amp racks, and a speaker soca gets plugged into a dimmer, there's even more scope for letting out the smoke...

 

That's kind of my point... it shouldn't be an issue if you ensure that you know what way of each soca goes to the correct fixtures.

[Simon Lewis]

...and if you don't, I'd like a quiet word with you... I've had a belt from a faulty soca shell, fortunately on the stage, rather than above it.

 

...and that would be quite understandable - especially given the somewhat basic construction of the original Socapex connectors compared to more modern (improved) lookalikes http://www.blue-room.org.uk/public/style_emoticons/default/biggrin.gif

 

However, if your earthed shell Scoapex was used with that hoist controller, the shell would become live anyway...

 

Therefore, if earthing the shell was problematic, I would prefer cables to made using the advice given in BS7909:

 

 

permanent durable rubber type sleeving is used to over-sleeve each conductor connection and a protective insulating boot is placed over all the conductors housed within the metal shell in such a fashion that failure of a wire or connection cannot result in the shell becoming live

 

 

 

 

That's kind of my point... it shouldn't be an issue if you ensure that you know what way of each soca goes to the correct fixtures.

 

Understood.... but the risk is when two or more soca ends come to (say) a dimmer rack with a hoist control on top, and the enthusiastic but less than competent crew plugs a socapex cable into the wrong device.

Ok - we should supervise, label, colour code etc., etc. but the issue is that it's still possible to do or make a simple mistake with...

 

 

 

[Andrew C]

Therefore, if earthing the shell was problematic, I would prefer cables to made using the advice given in BS7909:

That hadn't been invented back then, and yes, it was a "proper" Socapex.

We went with "All exposed parts liable to become live in the event of a fault shall be bonded to earth".

 

[bigclive]

Socapex is a "grandfathered" connector. Something that filled the requirements back when the touring and event industry was new. These days if a new connector was being chosen it would probably be different, but the fact it's already widely used means it's probably going to be here for a while (gritty threads and all).

 

It would be nice if a new connector did become available in the style of a 18 pin Ceeform. Something easy to mate and rugged enough to withstand the abuse of a load-out by random local labour. I wonder if an all-plastic soca is viable? A version with keying for completely different applications would be good. Audio versus power for instance.

 

The most redeeming features of soca as it stands are:-

 

Drags easily without snagging.

Lockable.

Fairly rugged.

compact for number of circuits.

 

The undesirable features are:-

 

One connector used in many different applications and wiring systems on a single site.

Ungrounded shell due to the complexities of having multiple circuits, potentially from different sources.

Prone to thread damage making proper mating harder. A significant issue with some crew.

Not water resilient with high risk of tracking between pins and shell.

No anti-tracking dams or standoffs around pins at mating side.

Many brands that are not all fully compatible.

Bad mating can result in significant internal burning of contacts and plastic.

A pre-damaged connector can go on to damage every other one it's mated with.

 

I could see a real advantage to a new dedicated Ceeform style 18-pole connector in black with slightly bigger or longer pins, anti-tracking dams/sleeves and the inevitably bigger case, but that would probably be no worse than a typical 32/63A size plug/socket.

[Simon Lewis]

I could see a real advantage to a new dedicated Ceeform style 18-pole connector in black with slightly bigger or longer pins, anti-tracking dams/sleeves and the inevitably bigger case, but that would probably be no worse than a typical 32/63A size plug/socket.

 

I think this would be an excellent idea... but one that would need considerable clout to develop and push through... (perhaps similar to when motor control cable connectors moved from 3 pole to 4 pole yellow Ceeforms...

 

Cost could be an issue... for example, devices like the PA CON 19 pole bayonet style connector (popular for use with certain brown painted speakers) costs up to three times Socapex compatible connectors. Any potential replacement needs to be affordable to gain traction.

The other thing is ubiquity... We use Soca because it is almost a universal 6 circuit 1.5mm^2 or 2.5mm^2 extension lead, and as such a few spare lengths could be used for lighting, audio or hoist power/control. Being able to use the same cable for so many functions is probably its strongest point and its greatest weakness...

[indyld]

Add to that:

 

Has a keying system that doesn't habitually wear through and lead to incorrect pin alignment and then takes all manner of ingenuity to secure again in the hope of not having to re-terminate the whole thing again from scratch.