Advise on SY termination (Stage Lights)

[JohnW2]

SY is a control cable, and is described as such on all manufacturers data sheets, and offers no screening, the braiding is full of holes.

Like the braiding of many coaxial cables used for RF, you mean?

Kind Regards, John

 

[davelx]

It's not black and white.
The filling factor of the braid has an impact on its screening effectiveness at different frequencies, so it depends on the frequency range you are trying to screen against as to how effective a given braid will be. You need a higher filling factor to screen against the high frequency components of a wide bandwidth transient such as a switching arc in the local area, than you do so screen against a UHF TV signal.

In addition, the braid on an aerial coax is not primarily there for screening, it is an integral part of the design of the cable to provide the correct characteristic impedance to efficiently transfer the maximum signal from the source to the receiver,

 

[davelx]

Well I'm sorry to say just because there are holes it does not mean that this stuff is screened.

.

Sorry, I don't understand that. I'm not aware that anyone has stated that the holes mean it is screened!!

 

[deadshort]

screening purposes having experienced interferance

The jobs backwards ! You would screen all audio cabling and use a 'balanced 'system with the screen earthed at the sound desk end to avoid earth loops. If the source is unbalanced,ie a guitar pick up, you would use a DI box.

LED stage lighting with DMX control is now standard, even in schools ! No dimmers required just 230v mains ! And a DMX signal cable

DS

 

[SUNRAY]

The jobs backwards ! You would screen all audio cabling and use a 'balanced 'system with the screen earthed at the sound desk end to avoid earth loops. If the source is unbalanced,ie a guitar pick up, you would use a DI box.

LED stage lighting with DMX control is now standard, even in schools ! No dimmers required just 230v mains ! And a DMX signal cable

DS

Yes DS I do know how audio works, I don't claim to be the worlds expert but I have been involved to some degree or other for some 55 years. My Public Address business was registered in 1977! Interference suppression is very much a 2 way street, good housekeeping on both sides and the jobs a good'n. Just ask an AFILS installer or user!
LED stage lighting with DMX control is NOT YET standard, ESPECIALLY in schools! dimmers ARE STILL VERY MUCH required!
I have some regular involvement with a number of local schools [about 10] and several theatres [2 pro & 3 AmDram] and not a single one of them has ditched incandescent lighting yet. Groups ESPECIALLY SCHOOLS cannot just find £20K to buy 200 LED fittings to replace their perfectly serviceable 50 Strand fittings.
Next month I am moving a whole lighting system which I installed 10 years ago to a schools new building. They are very happy with their 10KW of lights. They don't know about yet but I will add DMX to the 4 IWB's just in case they do go LED in the future.
In the Christmas break I am moving the majority of a schools stage lighting to a different hall [the old gym], again it is IWB's and dimmer packs, again they don't have any inclination to move over to LED's but I will add DMX to the connexion box's of the IWB's for the future.

 

[deadshort]

Yes DS I do know how audio works, having been involved professionally for some 55 years. Interference suppression is a 2 way street, good housekeeping on both sides and the jobs a good'n.
LED stage lighting with DMX control is NOT YET standard, ESPECIALLY in schools! dimmers ARE required!
I have some regular involvement with a number of local schools [about 10] and several theatres [2 pro & 3 AmDram] and not a single one of them has ditched incandescent lighting yet. Groups ESPECIALLY SCHOOLS cannot just find £20K to buy 200 LED fittings to replace their perfectly serviceable 50 Strand fittings.

I stand corrected.

I supose it depends on where you live.

Kind regards,

DS

 

[deadshort]

Not correct, T&E is adequately acceptable for such purposes, in fact I have a school job lined up for the Christmas break which has been spec'd as 1.5 T&E in cable basket. This is for 15A sockets on dimmer packs with 13A C type MCB's.

Do you mean 10a ?

Regards,

DS

 

[SUNRAY]

Do you mean 10a ?

Regards,

DS

No I mean C13A

 

[deadshort]

Interesting, what make are the dimmers?

Thanks,

DS

 

[SUNRAY]

Interesting, what make are the dimmers?

Thanks,

DS

Strand and Anytronic
Edit: Strand use MCB's with an auxiliary contact for neutral.

 

[ban-all-sheds]

Well I'm sorry to say just because there are holes it does not mean that this stuff is not screened.

 

[ban-all-sheds]

"SY control cables are not suitable for fixed wiring applications requiring compliance with the requirements set out in BS7671."

Do they give a clue as to which regulation(s) they believe it contravenes?

 

[JohnD]

I'm puzzled that they still seem to be re-equipping for tungsten lamps.

Old Strands are ten a penny in skips and on ebay.

The cost of electricity is huge.

edit
have seen the earlier post now.

 

[SUNRAY]

Old Strands are ten a penny in skips and on ebay.

Funny thing is: one group I know were trying to get some 'old Strands' for a retro effect expecting them to be very cheap, on the contrary it aint easy finding them under £100 which of course is more than the originally cost.

 

[JohnD]

they've tried ebay? I saw some follow-spots much less. Travel can be an inconvenience.