Earthing a Televez IRS System

[badgeroi]

I am new to this industry but have some experience as an electrician. I am working with a company installing Televez IRS Systems for local housing associations in the UK.

We are powering the system from a 240V communal lighting circuit in most cases through a spur with a 3A fuse protecting the power supply. The power supply has 240V in and 12V out.

All the 240v mains equipment is usually installed under the stairs or in an electric cupboard and a 4mm earth and single coax cable with the 12v feed run from there to where ever the mast and televez equipment is on the outside of the building.

Can someone please explain why a 12v system is earthed to the 240v supply. Surely this is a dangerous practice. Televison sets are double insulated so doesnt this cancel this type of protection as well????

 

[Topper]

Hello

Welcome to the forum badgeroi

This is a enthusiast/hobbyist site and the ins and outs of earth bonding are not really relevant here assuming someone was able to answer your questions

 

[rolfw]

There are several threads in this section regarding this, IRS Earthing Thread being one of them.

But as Topper says, we are a hobby forum and whilst many of our contributors are IRS installers, we no longer discuss or advise on commercial systems.

 

[Channel Hopper]

The earthing is there to protect the user, not the equipment.

Earthing satellite items to a common ground, minimises the internal voltages arising when a system covers more than a couple of floors. It should reduce the static discharge one may get when connecting something to the socket.

Additionally the earthing outside equipment is mainly for lightning protection, not that it will do a lot, but it provides one relatively quick path for the strike to ground, rather than through the sockets dotted round the property.

Mind you a lot has changed from my time with wiring regs.

(oh, and unless it is a new kid on the block, it's Televes)