Disco light connector thing?!

[Jivemaster]

you should only draw 5A per circuit because it's 5A cable!

No its 5a flex BUT there are only two neutral lines so 5a/chan sends 10 amps up each 5a neutral line. This cable is ok in a disco chase environment as some lights will be off at any time but if all the lights can come on together then its only 2.5 amps,

[Brian]

I certainly wasn't suggesting that anyone use T&E as a 'flex', only that earths do not have to be the same size as the main conductors.

 

the regs state that up to about 10mm the earth should be the same size as the phase

True, actually up to 16 sq mm, but you can use a smaller earth as long as you do the earth loop impedance calculations.

 

Although regs don't apply here because it's not an installation.

 

be aware that the pins in the panel mount connectors can over time move so they are slightly proud

Ah yes, I'd forgotten that little nasty. Brings back horrible memories of my disco days.

[Ike]

the regs state that up to about 10mm the earth should be the same size as the phase

Where do the regs say this? If you use the table it should be the same as the phase up to 16mm and if you use the formula it is usually quite a lot less.

 

Edit: oops Brian got there first.

[Light Console]

Just to add another spanner in the works, hopefully the Earth or CPC will never conduct anything anyway. It should not form part of the circuit unless under fault conditions - when amazing currents can flow until somthing trips/fuses.

Or is it too late and I have my wires crossed?

[Brian]

...hopefully the Earth or CPC will never conduct anything anyway. It should not form part of the circuit unless under fault conditions...

No, you are spot on. What confuses many people is that the current rating for a cable is determined to be the current which raises the temperature of a cable to a given amount over a long period of time, it has little to do with how much current a cable will carry.

 

Example...a piece of 5A fuse wire is just 0.07 sq mm 'big', a piece of '5A' cable is 0.75 sq mm 'big' (ie 11 times bigger) which means it will not fuse until at least 55A. By this time upstream fuses/breakers will have tripped.

[themadhippy]

And dont forget when doing earth calcuklations the max permited voltage to earth before protection circuits kick in is 50 volts,not 230v

As for those bulgin connectors id be tempted to change them for these

http://custom1.farnell.com/cpc_images/cpc2004/size3/CN07195-01.jpg

[Wilf dLampy]

As for those bulgin connectors id be tempted to change them for these

I'd be tempted to change them to socapex

[Ike]

As for those bulgin connectors id be tempted to change them for these

Funnily enough thats exactly what I did change them to!

[v8dve]

Yes, I changed from Bulgin to Elvcon, but then dumped them and changed to Socapex, albeit 10 times more expensive, but far superior and something I should have done in the first place had I been able to afford to.

[Ike]

Yes, I changed from Bulgin to...Socapex, albeit  10 times more expensive, but far superior

Not if you want a small, lightweight connector with terminals and cable clamp designed for small cable.

[Djbarryblue]

Dont fancy sticking a socapex connector on the back of a light box or a ryger foot switch a bit extream !!!! ** laughs out loud **

[Jivemaster]

The Bulgin 551 and 552 connectors should be replaced by the reverse gender compliment when appropriate these are 9xxx series and the cable connector is a socket the panel mount is a plug. These are designed for the standard 7-core cable and fit in the hole vacated by the outgoing connector and have appropriately sized cable clamp. They can be bought from RS Maplin Light Engineering uncle tom cobley and all. Dont taint a pro lighting connector system with DJ screens and traffic lights.