My friend has a conundrum regarding earthing the metal parts of his garage. It's an extension to his home which is on a TT supply, It's of concrete block construction with a metal roof, attached to timbers but touching 3 RSJ's which supports the whole roof. None of which is bonded. There are tw/e cables crossing over the beams, so I suggested 10mm equipotential bonding from the beans to the MET. Question is, what needs to be done with the roofing sheets, as bonding could be problematic and cause the roof to corrode? Any ideas would be most welcome.
 
My friend has a conundrum regarding earthing the metal parts of his garage. It's an extension to his home which is on a TT supply, It's of concrete block construction with a metal roof, attached to timbers but touching 3 RSJ's which supports the whole roof. None of which is bonded. There are tw/e cables crossing over the beams, so I suggested 10mm equipotential bonding from the beans to the MET. Question is, what needs to be done with the roofing sheets, as bonding could be problematic and cause the roof to corrode? Any ideas would be most welcome.

But what potential are these beams introducing?
 
Welcome to the forum, thanks for joining and asking your question! Have you got any photos of the job? It may help our members to give the appropriate advice!

Thanks
 
Thanks, I did the resistance check to the beams and it was 24K ohms, so in theory isn't extraneous, but I didn't check the roof sheets as they were touching the beams anyway. I'm assuming the equipotential bonding still applies to the the beams regardless as they are structural steels and within touching distance, however, it would appear to introduce an unnecessary risk, so perhaps bonding isn't the answer. It's a shame there's not more clarity in the regs for differing construction methods, and it leaves installers in a damned if you do or damned if you dont scenario.
 
Last edited:
Thanks, I did the resistance check to the beams and it was 24K ohms, so in theory isn't extraneous, but I didn't check the roof sheets as they were touching the beams anyway. I'm assuming the equipotential bonding still applies to the the beams regardless as they are structural steels and within touching distance, however, it would appear to introduce an unnecessary risk, so perhaps bonding isn't the answer. It's a shame there's not more clarity in the regs for differing construction methods, and it leaves installers in a damned if you do or damned if you dont scenario.

But if they aren't extraneous then why connect them to to the electrical system?
 
Thanks, I did the resistance check to the beams and it was 24K ohms, so in theory isn't extraneous, but I didn't check the roof sheets as they were touching the beams anyway. I'm assuming the equipotential bonding still applies to the the beams regardless as they are structural steels and within touching distance, however, it would appear to introduce an unnecessary risk, so perhaps bonding isn't the answer. It's a shame there's not more clarity in the regs for differing construction methods, and it leaves installers in a damned if you do or damned if you dont scenario.
Not really its clear in black and white. Not knowing the regs isnt the regs books fault.
 
Was there any toast to go with the beans?
Just joking I think that you ment beams and not beans I am dyslexic and simple mistakes tend to jump out to me not that my spelling is any better at times when I look in the dictionary for the spelling of a word I have started with the beginning of a letter and worked all the way to the next letter and still not found the word I was looking for and have had to find a different word for the same thing. Regards Poppy Ann
 
Best EV Chargers by Electrical2Go! The official electric vehicle charger supplier.

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Advert

YOUR Unread Posts

Daily, weekly or monthly email

Advert

Thread statistics

Created
spantheman,
Last reply from
PoppyAnn,
Replies
11
Views
1,278

Advert

Back
Top