Lighting protection via 10mm bonding cable

[D Skelton]

So, I'll start by saying that my knowledge of the regulations surrounding lightning protection systems are limited, it simply isn't work that we as a company carry out as we leave it to the specialists.

During an EICR I find what looks to be an old aerial pole on the roof of the building, looks like a 3m scaffold pole just bolted vertically into the roof structure. Now this has been bonded back to the MET with 10mm bonding cable. It's clearly not an extraneous conductive part and so the bonding needs removing. My question is regarding the code to give it. The chances of it being struck by lighting are slim as there are higher buildings next door with proper lightning protection systems and charge dissipators atop. That said, without experience in lighting protection, is it up to me to make this judgement call and give it a C3 or should I just play it safe and C2 it? My gut tells me the latter may well be the best approach.

 

[HappyHippyDad]

Why would taking the bonding off make it safer Mr DS?
Is it because it is clearly not the correct method of lightning protection so would be better not to attract the lightning to that point?
I think Darkwood knows quite abit about lightning so I hope he replies.

 

[D Skelton]

Why would taking the bonding off make it safer Mr DS?
Is it because it is clearly not the correct method of lightning protection so would be better not to attract the lightning to that point?
I think Darkwood knows quite abit about lightning so I hope he replies.

Bonding needs to be applied to lighting protection systems as they are extraneous conductive parts, however when a part isn't extraneous, and bonding the said part essentially turns your 10mm bonding conductor into a potential lightning conductor, this just ain't good really is it lol

 

[Rockingit]

Wasn't it a fashion though a while back to go bonding aerial masts and satellite dishes? Might be worthwhile asking if there was ever anything on it!

 

[Hobsoni]

I think that because you are aware of the potential hazards that it has to be noted as a C2. Is there no access for you to at least cut the 10mm (outside the property) off?

 

[davesparks]

Could it be an old CB or HAM aerial installation which would have required an earth connection to work? Although I'd have expected it to go to a rod rather than the MET.

 

[LeeH]

Could it be an old CB or HAM aerial installation which would have required an earth connection to work? Although I'd have expected it to go to a rod rather than the MET.

The only earth they needed Dave was through the coax shield.

 

[D Skelton]

I think that because you are aware of the potential hazards that it has to be noted as a C2. Is there no access for you to at least cut the 10mm (outside the property) off?

I could have done, but I was there to provide a report only, not to start chopping bonding conductors, regardless of any potential danger.

I gave it a C2 in the end but basically said that they needed to gain the advice of a lightning protection specialist.

Probably the best way to deal with it in my eyes. I've covered my backside but at the same time told them that it needs further investigation by someone who knows better than I do whether it should be there or not.

 

[Marvo]

If you decide to disconnect it I'd suggest a full risk assessment first including referring to whether charts for strike frequencies etc. I'd personally leave it connected to the MET. Is it against the UK regs to have an item connected to the MET if it doesn't qualify as extraneous conductive?

 

[D Skelton]

If you decide to disconnect it I'd suggest a full risk assessment first including referring to whether charts for strike frequencies etc. I'd personally leave it connected to the MET. Is it against the UK regs to have an item connected to the MET if it doesn't qualify as extraneous conductive?

I wouldn't know where to start with a strike frequency risk assessment, nor would I know whether the conductor's existence is actually dangerous, hence why I won't be touching it until a specialist in that area has given their advice.