Bonding to a Digital Aerial

[Sidewinder]

No mate it is vague and a lot of it rubbish tbh!

 

[kerching]

No mate it is vague and a lot of it rubbish tbh!

Ah, that explains a lot! Maybe the Merlot is not as strong as first antishipated then ! Must drink more, as a test.................... :Y

 

[ProDave]

I thought the CAI requirement for earth bonding was for COMMUNAL systems.

i.e where one distribution amplifier, or multiswitch feeds multiple separate properties, then the aerial cable must be grounded to prevent a fault in one dwelling introducing a voltage to other dwellings.

You can buy F connector grounding bars for this in much the same way as you can get grounding bars for cat5 networking cable.

A single aerial or satellite dish feeding a single dwelling has NO requirement to be bonded.

 

[Barx]

I haven't read through the docs linked int this thread but thought I would add this as it may help a little. I have no idea on the actual regs or guidelines for bonding tv equipment BUT I have recently done some CU changes in communal areas in blocks of flats. I the power rooms were relatively new TV distributions systems and YES these were indeed bonded with 4mm GY, Straight out of MET and then just linked from 1 unit to the next. Hope this helps a bit.

 

[Sidewinder]

I don't like the idea of creating a lightning magnet on the roof TBH!

I can understand the earthing of the communal systems to eliminate electrical faults, but, IMHO this would be better achieved by clever electrical isolation of the distribution points.

 

[batty]

I would agree with Slidey imagine if your aerial on the roof gets struck by lighning that bit of 4mm will not be very effective and its not going to do the internal eletrics much good either. We are in a strong signal area so can get a good picture with aerial in loft luckily.

 

[hxsarge]

asked a cai guy today and normally in small domestic settings where the aerial feed goes into a distribution center, he was trained to take a 4mm to the earth terminal on the distributor, this then bonds all cables that enter it and thus bonding the Aerial.

 

[RB2004]

Yep, CAI does indeed teach that you need to bond all outlets from any distribution point with minimum 4mm earth back to MET

Whether this is correct or not, as I am in agreement about making a lightening conductor out of the aerial... even domestic distribution equipment now features earth bonding points.. ive installed a few Loft boxes, which are designed for a domestic situation.. as well as various spliters and things and all feature proper earth temination points.. and in the instructions tell you to earth back to MET.

So it must be correct however bad it sounds as I would of thought somebody from the IET would of pulled up the CAI about it now.

It is indeed done for touch voltage, and also in the event that a device goes faulty and shoves 230v down the coax cable.

I guess its a case of which is riskier, and more likely to happen? lightening strike or 230v down the coax and or touch voltage.

 

[Sidewinder]

^ I've not had chance yet!

 

[SLIPSHOD & SLAPDASH]

Surely any system with a amp or switch would already have power & so an earth connection ?

 

[RB2004]

nope, most of these amps and loft boxes have flat twin cable flex... so no earth because they have a built in transformer and run on a low voltage and amperage.

the earth bonding isnt for the device itself its for bonding all of the outputs together back to the MET.

 

[SPECIAL LOCATION]

From here...

http://www.tlc-direct.co.uk/Technical/DataSheets/Labgear/MXPUHV.pdf

General Safety NotesTo avoid risk of electric shock during installation we recommend that the power unit and all associated TV

receivers, etc. are isolated from the mains until the installation is complete.

Fixed wiring for electrical supply to these products should be carried out in accordance with BS7671 (IEE Wiring

Regulations).

Distribution systems supplying signals to more than one household should comply with the safety

requirements of BS EN50083-1. This requires the system to be earth bonded or the use of isolated outlets.

Single dwellings.. Earth not required....

Or..

not required on multiple households if isolated outlets used!

:coffee