Another church question

[Steve_P]

I've been doing a bit of work on a church which is built on the top of a hill about 300 feet above sea level, the tower is about 100 feet high with open countryside all around.

I have my own theories here but can anyone give me a good reason to connect the lightening conductors, lead in the roof gullies or steelwork in the bell tower (top section of the 100 foot tower) to the MET? None of this metalwork is remotely near any of the electrical system and the 4 lightening conductors run down the outside of the tower to earth.

 

[Engineer54]

I've been doing a bit of work on a church which is built on the top of a hill about 300 feet above sea level, the tower is about 100 feet high with open countryside all around.

I have my own theories here but can anyone give me a good reason to connect the lightening conductors, lead in the roof gullies or steelwork in the bell tower (top section of the 100 foot tower) to the MET? None of this metalwork is remotely near any of the electrical system and the 4 lightening conductors run down the outside of the tower to earth.

As for steelwork in the tower, Potential flash over is the main reason, if open to the elements. (i'm thinking here of steel structure for the church bells) and should be connected to the LP system, not the installations MET. The LP system however should have a link from a down conductor to the MET!!

The bold type above i'm not sure what your saying here, so please explain!! lol!!

 

[MDJ]

I've been doing a bit of work on a church which is built on the top of a hill about 300 feet above sea level, the tower is about 100 feet high with open countryside all around.

I have my own theories here but can anyone give me a good reason to connect the lightening conductors, lead in the roof gullies or steelwork in the bell tower (top section of the 100 foot tower) to the MET? None of this metalwork is remotely near any of the electrical system and the 4 lightening conductors run down the outside of the tower to earth.

In a word, regulations, not sure of the reg number, a lightning conductor must be connected to the main earth terminal, everytime I fit one the specialist I employ to fit one insists on it and starts quoting regs, I also get a lecture about fitting surge protection to equipment as well, there must be something in it they keep on about it haha

 

[Steve_P]

Ok, a couple of reasons for asking. The steel in the bell tower as far as I know (haven't had access way up there yet but it was confirmed on the EICR) is connected to the LP but the LP is not connected to the MET. The company who installed it didn't say anything about needing a connection. The company who re-wired the church didn't connect it, and the company who ran a supply to an out building didn't notice it. The company who did their EICR last year did notice the lack of connections but also noted that there was no connection to the plastic incoming water supply or the lead in the gullies of the roofs. So, here's me, 5th spark on site in as many years and asked to look at the EICR, I took a mate with me today, second pair of eyes and all that. His take on this is that as the LP, lead and metalwork where the bells are (not open to the elements) have no electrical supply, connecting to the MET could introduce a current to somewhere there wouldn't usually be one. Although it's difficult to disagree with the logic, I did start doubting myself.

 

[Clive P]

Hi,
Just had a look on the net, English Heritage have a good downloadable PDF entitled 'Lightening protection on Churches'.

May be worth a look,

Regards.

 

[Clive P]

Hi,
Also on the same Google page is a PDF , 'Diocese of Rochester' that talks about bonding Bell Towers etc,

Regards.

 

[Steve_P]

Cheers Clive. Bonding to LP was always something that went without saying, just had to be done. Until today that is.

 

[Knobhead]

Looking at it from a pure physics point of view. A bond should be taken back to the MET from one of the ground spikes. Not from any point above ground and not to all ground spikes.
The reason (as I see it):
Take a point above ground and you will get a voltage gradient which will transfer to the MET and therefore the rest of the electrical system. Regarding the bell frame, either bond it to the LP system or the electrical system, not both.
Link all earth points and the MET becomes a marshalling point for the LP system and the earth bonds are likely to vaporise with the current being transferred.

This is a personal view, and something I’m willing to concede on given good reason. I.E. NOT the reg’s say………..

The reg’s and physics just don’t tally.


Come on E54, you’ve got a target in you’re sights.

 

[Silly Sausage]

Aye, I've been enlightened by God's thunderbolt once, when I was in the Mental Hospital.

Regarding the OP, I'd call the Lightning experts in.

 

[Engineer54]

Looking at it from a pure physics point of view. A bond should be taken back to the MET from one of the ground spikes. Not from any point above ground and not to all ground spikes.
The reason (as I see it):
Take a point above ground and you will get a voltage gradient which will transfer to the MET and therefore the rest of the electrical system. Regarding the bell frame, either bond it to the LP system or the electrical system, not both.
Link all earth points and the MET becomes a marshalling point for the LP system and the earth bonds are likely to vaporise with the current being transferred.

This is a personal view, and something I’m willing to concede on given good reason. I.E. NOT the reg’s say………..

The reg’s and physics just don’t tally.


Come on E54, you’ve got a target in you’re sights.

Yes, ...i should of made myself a little clearer when i said down conductor, i was talking about a below ground connection, either at one of the rods, or to a conductor linking the down conductors to the other rod's ... lol!!

I've yet to see a bell tower where the bells are totally enclosed, so they would be open to the elements, ...pretty pointless having bells if they can't be heard over any distance!! So should be connected to the LP system, not the electrical installations MET.

The LP system is bonded to the MET, to decrease the possibilities of lightning flash overs to any earthed/bonded metalwork. These day's any stray lightning currents reaching the buildings electrical system can be protected against by surge protection devices/modules...

 

[Knobhead]

I've yet to see a bell tower where the bells are totally enclosed, so they would be open to the elements, ...pretty pointless having bells if they can't be heard over any distance!!

All Saints Nottingham. One of T.C. Hines masterpieces. The bells were too loud and the louvers had to be bricked up on the inside.
I lived opposite the bell tower. I couldn't turn the bloody alarm off on a Sunday morning.

 

[Silly Sausage]

Vyvyan from The Young Ones shouts at the church - YouTube

 

[Knobhead]

OK, that was me.

 

[Silly Sausage]

I wasn't Rick!
But did have a jacket with Cure badges on at the time....hahahaah... happy days!

 

[Engineer54]

Any external metal systems such as guttering etc, should also be bonded to the LP system... I think this is what you meant in your OP...