100volt speaker system cable question

[dannyboi2003]

Hi guys, apologies if this should be in the audio visual section but it's more an electrical question really. To cut a long story short we are having extension and refurbishments works at my workplace, I'm responsible for the IT systems etc. including the speaker PA system, the contractors have extended our existing audio installation but they have only used single insulated speaker wire, whereas the original is using double insulated. Can anyone confirm if double insulated cable has to be used (with a reg number if possible) bearing in mind it's a 100volt line from the amplifier. Just want to conform if I'm right or wrong before I ask them to replace the cabling.

Thanks guys
Dan

 

[Chri5]

I've seen loads of tannoy / pa kit in speaker cable, normally it's 42 strand which would be just under 1.5mm sq.

I've also seen it done with 2 core lighting flex, and 1.0mm twin and earth.

What sor of runs and how has it been installed (trunking, thrown over false ceilings, under false floors, clipped)?

 

[bernardgreen]

As the voltage can exceed 100 volts at high volume levels then cable rated at 230 volt is the prefered option and therefore should be double insulated. If nothing else it looks like mains cable and may therefore be treated with care needed with that level of voltage to avoid electrical shock.

Testing for dead will show dead if the speakers are silent, but don't be holding the bare cores when there is an announcement or the music starts.


I found this site

http://public-address-info.co.uk/pa_installation_tips3.html

 

[dannyboi2003]

Hi Guys,

Thanks for the replies, sorta confirmed what i was thinking that being as 100volts could be present then double insulated it should be.

Chri5 - The cabling is mostly in tray/basket and then just bobs across the false ceiling to each speaker from this.

Bernard - Thanks for the link to that site, it will be a handy reference point.

Thanks
Dan

 

[Robin0577]

I don't know of any official requirement for this but where I work we only install loudspeaker cable which is designed as such, and more to the point printed as such at regular intervals on the sheath. This, for example for 100v line installations...

http://www.canford.co.uk/Products/20396/34-226_CANFORD-HLS-LFH-CABLE-2-core

Or this for low impedance...

http://www.canford.co.uk/Products/2003388/34-281_CANFORD-GPS-LFH-1.5-CABLE-2-core