simple DMX control of par cans

[S&L]

If I work a big show, someone else gets involved with the lighting and I concentrate on sound but for bars, weddings, small halls, I take out a simple and old fashioned set up and someone with me runs the controller.

here is my existing set up, used for simple bar/small hall bands.

2 no. tee bars each hanging 4 no. par56 300w par cans

each tee bar pre wired with a distribution box. circular bulgin connector in, 4 no hard wired outs, one to each par can

I have been running two bulgin cables from an analogue dimmer controller - one to each tee bar.

the tee bars are mirrored so that sitting either side of the stage, the 4 light channels repeat on either side of the stage.

 

for various reasons we are looking to convert to DMX but keep these par can tee bars.

 

I was looking at a Transcension CDP-405 dimmer pack. this has a single power supply in and a choice of using either 4 iec outlets OR 2 circular bulgin outlets. 5 amp max per circuit

can anyone see why I can't or shouldn't run as follows:

 

simple DMX desk foh with dimx cable to stage.

local 13A power connection to CDP-405, positioned out of the way on stage.

two bulgin cables out of the pack, one connecting to each of the existing tee bar distribution boxes.

 

comments? thoughts? this seems a relatively cheap way of introducing DMX control and as long as the dimmer pack lasts for two or 3 years it would more than pay for itself, running once every two weeks or so.

 

[greenalien]

Looks like a good choice - reusing your Bulgin connectors is a good idea, much tidier than separate IEC connections, and the controller has sufficient capacity to handle a couple of 300W PAR cans on each channel. Go for it!

[david.elsbury]

Are your Bulgin cables male to male (with pins on both ends) or male to female, with male pugs on the light bars? If M-M, I'd be looking to move away from this system, as the risk of touching the exposed pins (although small) could result in a shock.

 

For what it's worth :)

David

[S&L]

Are your Bulgin cables male to male (with pins on both ends) or male to female, with male pugs on the light bars? If M-M, I'd be looking to move away from this system, as the risk of touching the exposed pins (although small) could result in a shock.

 

For what it's worth :)

David

 

male to female, live end always female - why would someone wire a cable male to male?! very worrying.

[themadhippy]

why would someone wire a cable male to male?! very worrying.

because the original bulgin range didn't have a cable mount socket,or if they did they were rarer than a rare thing on a rare day .Hang on a sec, 4 cans on 8 pins?

[sleah]

.Hang on a sec, 4 cans on 8 pins?

 

Eye.

 

4 x lives

3 x neutrals (usually two used, one left unused)

1 x earth

 

So long as it's all wired in 8 way Bulgin it's completely safe, apart from the not very well designed connectors and of course the possibility of overloading neutral (often only one conductor used even if two pins are used), especially if all four cans on together.

 

So now you know! :D

 

Edit to add: Bulgin 8 ways even the bl00dy females can give you a buzz as the metal can be rather close to the top on older connectors. The male connectors actually weren't mush worse than the females for shock hazard! :o

Evil things. Every technician/DJ should start their career using them... B-)

[S&L]

why would someone wire a cable male to male?! very worrying.

because the original bulgin range didn't have a cable mount socket,or if they did they were rarer than a rare thing on a rare day .Hang on a sec, 4 cans on 8 pins?

 

yes, presently adapted from one of NJD's 7 pin outlets - earth, 2 common neutral pins and 4 switched live pins.

on the proposed dimmer pack it has 2 bulgin outlets and 4 channels - the manual is really light on detail but it's 4 channel so can only be wired a few ways and making it live and putting a meter across terminals should verify the connection pattern - if the delivered manual is just as vague!

[dbuckley]

because the original bulgin range didn't have a cable mount socket

 

Correct; back in the day there were Bulgin plugs that went on cables, and Bulgin sockets that went on things. I still have a Bulgin extension "cable" from back in the day, the "socket" end is a chassis socket in a conduit termination box.

 

Despite using them all over the place for years, I never got so much as a tingle from these connectors. I still use them for fluorescent practicals on stage, because they are about the only common stage connector that has more than one live pin, this side of C17s.

[serious_sound&light]

I have never had any trouble with Bulgins, apart from trying to find a 7-core + earth cable that fits them properly. The male connectors are designed to be touchproof (to a British Standard finger - yes, they do exist, in both rigid and articulated versions; I was once tasked with calibrating one of the latter). Yes, having live metalwork in full view may be disconcerting, but we know not to touch, even if we could.

 

I have never had any trouble with Bulgins, apart from trying to find a 7-core + earth cable that fits them properly. The male connectors are designed to be touchproof (to a British Standard finger - yes, they do exist, in both rigid and articulated versions; I was once tasked with calibrating one of the latter). Yes, having live metalwork in full view may be disconcerting, but we know not to touch, even if we could.

[david.elsbury]

Yes, having live metalwork in full view may be disconcerting, but we know not to touch, even if we could.

Does a small child (with a small finger) know that? Appreciate that these are not domestic connectors, but I don't think that "these passed standards testing" and "we've done it this way for ages" is an acceptable way to look at the problem, particularly when there are now female versions of the same connector available.

 

2c

David

[themadhippy]

particularly when there are now female versions of the same connector available.

Even better is the newish 7 pin iec connector,that fits the same size hole as the old bulgins

[Stuart91]

My fingers are probably significantly fatter than the British Standard, and I have received shocks from both male and female Bulgin connectors in years gone by. (The female was the outlet on a chaser unit, the trailing females mounted on cables seem better).

[dbuckley]

I have never had any trouble with Bulgins, apart from trying to find a 7-core + earth cable that fits them properly.

 

Halfords. Say no more. Don't want to end up on Dodgy Technicians :)

[sleah]

I have never had any trouble with Bulgins, apart from trying to find a 7-core + earth cable that fits them properly.

 

Halfords. Say no more. Don't want to end up on Dodgy Technicians :)

 

Maplins sell it too, it's where I used to get it before we had Halfords ;) Slightly less obvious :** laughs out loud **:

[Brian]

Halfords. Say no more. Don't want to end up on Dodgy Technicians :)

 

Except a lot of the stuff sold for trailers isn't rated for mains use.