Testing earth bond on a sat dish

[Toonlad]

I will try and keep this brief, my firm has a branch of sky installers. They are now being asked by sky to generate some sort of proforma to verify that....... In particular to a shared dish scenario,( ie 2 tenants)
That the dish is earthed, they do this via a 4 mm cable and a earth rod.They are requesting a low resistance measurement as proof.Also they want the verification results recorded on made up sheet. Not a minor works. Like i asked do you know how to identify a tn-c-s for example or TT. I was talking another language i swear LOL

Obviously all the usual springs to mind here, test equipment, minor works cert, competent persons.

They asked my opinion and gave the usual, electricians take on it, but thinking about it i remember somewhere;
i do believe if you can see this bonding conductor along its entirety then it is not necessary to do an R2 on it. Just cant find the reg stating it. Therefore no testing required.

But now reading in between the lines why has sky started asking authorized dealers of sky installs to do this all of a sudden.But more alarmingly on a non conforming format.I am thinking an umbrella for something.

Your thoughts gentlemen.

 

[sparkdog]

Never heard of a Sky dish being bonded before.The LNB (thing on the arm that picks up the signal) is earthed through the outer braiding of the cable anyway.

 

[Toonlad]

It is where they have a free shared dish system, 1 dish 2 neighbours and a quad lnb. If you think about it the 2 houses are now bonded via that dish and lnb and coaxs So they bond the dish and knock in a spike just below.. Also IRS systems in multi dwellings too, normally back to the MET, or pick up off the supplying spur at the launch amp.

Well i found a dvd with tony cable saying if you can see a main bonding conductor and follow the cable from Ato B then the R2 does not need to be measured, just cant find reference in the BRB, unless its an Niceic thing.But it still remains to be seen who is going to measure this R2, Looks like a Part "p" Domestic Dish Installers, course is in the making.

 

[UNG]

I would think it is a bit poinless banging a rod into the ground without checking the resistance

I spent a few years installing and repairing radio comms kit on the rooftops of buildings and it is surprising how many grounding spikes don't give good readings or multiple spikes are needed to get the resistance down

 

[baldsparkies]

Earthing a satellite dish Political correctness gone mad. Comes under placing out of reach
This seems a pointless task and reminds me of the bonding panick scenarios that came with the 1st edition of the 16th wiring regs

 

[confused-fuse]

is this for lightening strikes ??? sounds like it if thay want a earth rod banging in the ground .. sticking a earth to a dish will correct me if im wrong will mean your making the earth path wider so if thay is a earth fault from 1 client system will this go to the other clients system ???? the mind boggles lol

 

[grimbley2001]

Communal installtions must be earth bonded according to CAI regs, this includes outputs of switches, electronics themselves, and any dish or aerial reception equipment. Since individual flats are now electrically connected, a common earth must be found. This would usually be the building PME but in some circumstances, where no communal PME is available, a spike may be required.

As mentioned earlier in the thread, there is not much point connecting an earth to a rod with a massive resistance. I have heard of people soaking the ground during measurement to get acceptable reading but again, this defeats the purpose.

The bonding ensures that all outputs have a common earth and therefore reduces cross talk and other signal issues and protects engineers working on systems (imagine a customers equipmment went live or if some maniac plugged the coax into the mains!) same scenario for dish and aerials.

also to protect residents if system goes live. Pleas visit visit CAI.org for more details. The are very helpful and if your company has ASHA status they will be CAI members and have access to the support they offer.

Sky will simply be looking for compliance to industry regs and to ensure customer / engineer safety/ system functionality. Sounds like good sense to me.

you would think the responsibility would lie with the contractor for the system safety but the contracting company ultimately holds the legal responsibility i think.

They are probably just looking for the resitance reading from the rod itself to ensure it falls into the regs laid out by the CAI.

Lightening protection is a contentious issue. If the dish is within 2m of the roofline it required to be lighteneing protected. All aerial masts should be lighteneing protected. If there is no LPS on the building, a 16mm earth should be run directly (straight line) to earth spike. Bit expensive, again, i would seek CAI guidance as Sky will ultimately be taking their steer from them.

What company is it you work for?

Cheers

Grimbley2001