Earthing a Multiswitch

**satelliteman** · 02-06-2008

As part of BS EN 60728:11 2005 : it says that anything more than a Sky Plus and aerial at points to rooms really needs earthing or making electrically safe in some other way.

This is electrical safety for 'Cabled distribution systems for television, sound and interactive multimedia signals'. Part of BS EN 50083/60728 Series.

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This has to be done on commercial systems as standard ! and as we are now seeing more and more complexed domestic systems out there around the home, earthing procedures have to be considered.

May sound daunting but is very simple.

Most switches come with earth bars attached to them anyway. You just need to earth all input and output cables to the main earth via a minimum of 4mm earth cable back to the PE (primary earth).

An electrician can do this job without too many problems.

Paul

101michael · 05-07-2008

When i purchased my antiference multiswitch i also purchased its earth bonding kit...

This included 'quick fit' f type modules which slide onto the ins and outs of the multiswitch connected together with earth wire, im a bit worried that it may slightly degrade signal quality that now i have the coax going through another connecter, would it be best to just have the wire screwed around the ins and outs rather than through the included push on connectors?

**satelliteman** · 05-07-2008

Originally Posted by 101michael

When i purchased my antiference multiswitch i also purchased its earth bonding kit...

This included 'quick fit' f type modules which slide onto the ins and outs of the multiswitch connected together with earth wire, im a bit worried that it may slightly degrade signal quality that now i have the coax going through another connecter, would it be best to just have the wire screwed around the ins and outs rather than through the included push on connectors?

There will be no loss if correct connectors are fitted.

You can connect the 4mm earth cable to the multi-switch earth tag itself if you wish.

101michael · 05-07-2008

hm, well im a bit confused now...

There is an earth bar at the side of the multiswitch, once all the ins and outs are connected via the earth bonding kit does this need to go through the earth bar before the main earthing, or can i bypass the earth bar and go directly to the earth cable which is coming out of the consumer unit?

thanks

**satelliteman** · 05-07-2008

Connect a 4mm earth to the multi-switch either as per the bonding bars kit OR just connect the earth directly to the multi-switch via it's earth tag (this will be a hole with a screw somewhere on the switch)

Both will serve the same purpose.

***Note***
If your not qualified to do the above work, consult an electrician.

Satman

101michael · 05-07-2008

OK...i sort of think i understand..

but take a look at this _http://www.antiference.tv/isys7-installation-schematic

Right, i have the earth bonding and connecting all ins and outs together...but why do that if i can just connect my earth straight to the earth post?

Or am i meant to connect all ins and outs to the earth post too?

Sorry if i seem to be repeating the same question. I will get my electrician to take a look, but i just like to know whats meant to be done prior.... thanks again

**satelliteman** · 05-07-2008

OK,

On larger systems ie. flats and apartments where say 100+ sub feeds are connected. If you require to service the switch Or replace it, then when you take the switch out, each subscriber cable will still be earthed.

If you connect to the earth tag only. When the switch is taken out to be replaced, the sub cable are not in the protection zone.

As it's only 16 cables or so and it's domestic, you can just connect to earth tag Or continue to install the kit.

Hope you understand my explanation

Paul
Satman

**rolfw** · 05-07-2008

If you install the earthing kit, then also earthing the earth tag on the switch is probably overkill, but it only takes one further piece of cable to do the lot.

It is the UK only which insists on this double earthing, not the same on the continent I believe.

101michael · 05-07-2008

sateliteman...

ok i understand BUT:

why not connect the say, 20, multiswicthes in a star architecture from their earth post to the main earthing point? so if you remove one switch then the others are not affected?

Is this possible? im not an electrician so i have no idea, does this mean all ins and outs are pre looped within the switch to the earth post, if not why not?

Sorry about all the questions, ill still get my electrician to have a look, but i just like to understand as much as possible...rather than nod accordingly.

**satelliteman** · 06-07-2008

Not all larger systems can be wired in a star configuration.

If your going to earth a multi-switch back to the board, even if it's a domestic set up, you need to also make sure you are using benchmarked cabling (copper to copper)

Other cables may not carry the current and trip the RCD in the event of a fault.

** INFO: The maximum resistance between the buildings earth point (PE) and the furthest point on a system is 3.5 Ohms. Now 2 Ohms of that is between the PE (primary Earth) and your earth bar at the multi-switch location. This shouldn't be a problem as your cable runs won't be too long.

** INFO: This method of safety provision ensures that any hazardous fault currents that maybe present on the distribution system are taken to earth.

** INFO: Either a faulty TV/ SAT RECEIVER or some other mains operated equipment being connected to the system would generate these hazardous voltages and pass them around the system unless some electrical protection is provided.

This info is mainly for IRS systems on commercial properties, ie. apartments, flats etc...

This can also apply to LARGE domestic set ups around the home whereby IRS systems are being used.

Note** If your not qualified to work with electrics around the home, consult a qualified electrician.

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Earthing a Multiswitch This section is for discussion on domestic multi-receiver systems for distribution of both terrestrial and satellite signals. Multiswitch, diplexer, triplexer, earct bonding, smart Priority switch, signal splitter, SCART doubler, video sender, remote extender, etc.

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