Main bonding in large industrial building

[johnboy6083]

yes you can. It must be labelled as usual, and of course the steel must be bonded to the main earth to the building. I would guess that it will be, but its worth checking.

 

[sterandall]

yes you can. It must be labelled as usual, and of course the steel must be bonded to the main earth to the building. I would guess that it will be, but its worth checking.

i never knew that, that makes life a hell of a lot easier now though thanks, the structural steel is bonded in about 240mm. When you say precautions must be taken against its removal is that just as simple as labeling it?

 

[johnboy6083]

the bonding connnection should be labelled with a label not less than that of a BS951 clamp. other precautions are things like not connecting to steel that is likely to be removedand maybe enusring that removal of any cable in the building by non sparks requires the permission of the electrical engineer.

 

[Engineer54]

If the building is all structural steel and has been bonded back to the MET at origin, you can safely say that the whole of the steelwork is one big bonding conductor that is interconnected by cross beams and sections etc!! haha!! Just try isolating all those parallel earth paths, ...no chance!! The chances are, that the structural steel of these buildings is also forming part, if not all of the earthing for the site too.

As you say, ...you can just link the steelwork to the system or service you want to bond out. In reality, the chances are it's already bonded by fixings etc,, but you will still need to make purpose made bond connections, to satisfy all the various requirements you have these day's...

Be interesting to know what sort of Ze and/or Zs values you get at the buildings incoming supply point??

 

[Knobhead]

When bonding the steel work use clamps for the connection or weld a bolt on, don’t drill structural steel. If you weld a bolt then put it inside the web out of harms way.

 

[netblindpaul]

I would concur with both of my learned colleagues above.

 

[sterandall]

I'll be using clamps on the structural steel, had a quick scan through the catalogue last night and found them.

Thanks everyone for all the help

 

[malcolmsanford]

malc mentioned about steel frame earlier. He is hinting at the fact that it is permitted to use any extraneous metalwork as bonding or indeed CPC, provided precautuions are taken against its removal, and it is of a suitable CSA, which 90% of steelwork on a building will be.

Thanks John yes that was what I was going to post next that the actual building frame will be the bonding conductor, but was not on the forum for the last few days, but you E54 and Tony sorted the lad out.

 

[R4BOE]

When bonding the steel work use clamps for the connection or weld a bolt on, don’t drill structural steel. If you weld a bolt then put it inside the web out of harms way.

hi whats the issue with drilling the structural steel work ?? we drill and tap the hole, clean the area where the crimp is to go from paint and install the bond accordingly ! just wondering if there was something wrong with this ??

 

[netblindpaul]

YES there is something VERY wrong with this, if you don't know then you should not really be doing it! Sorry.

 

[R4BOE]

do you fancy educating me then ?

 

[CrazyScozzese]

YES there is something VERY wrong with this, if you don't know then you should not really be doing it! Sorry.

Not very helpful.

 

[Engineer54]

In the real world, the chances are, there would be Nothing wrong in drilling and taping in substantial sections of structural steel work. We have to get approval on our projects for all such work from the Structural Engineer, but i can't ever remember being refused, ...even once!! Braised, spot, or exothermically welded studs are also useful for connecting bonding/earthing cables to steelwork

Different if you need to chop a lump out of a section of structural steelwork, but that would be an extremely rare occurance...

 

[R4BOE]

hi engineer, thanks for the info. i kinda thoght thats what netblindpaul was on about, i have never had this method questioned ! the plant were on is a large job and the enginners and fitters drill holes all over the place for securing plant and walkways etc and its never broughgt up any issues so i cant see how a M8 or M10 hole that has a bolt in it woulld make a hell of a difference pepole secure various items on the structural steal work on many sites and again never heard any one including site agents or the enginners bring the subject up , i am sure i would hear about it !

 

[Vandaft1980]

hi engineer, thanks for the info. i kinda thoght thats what netblindpaul was on about, i have never had this method questioned ! the plant were on is a large job and the enginners and fitters drill holes all over the place for securing plant and walkways etc and its never broughgt up any issues so i cant see how a M8 or M10 hole that has a bolt in it woulld make a hell of a difference pepole secure various items on the structural steal work on many sites and again never heard any one including site agents or the enginners bring the subject up , i am sure i would hear about it !

As you have said , steel erectors/structural engineers etc drill in to these beams to bolt in cross strainers so tapping/or bolting, an earth wire would be hardly putting any stress on the beem the removed swarf when drilling would be replaced with a bolt so the volume of the beam would be the same( the bolt would infact would be of stronger composite) so there for would not be any weaker

Also as you say roller doors etc are all fitted to structural steel work ,maybe we better do away with them and fire doors .