Over head gantry crane

[elecjones1666]

Hi Felo sparkies,
Just got a job in to put in to 3 phase feeds for two out side ganty cranes. There actually two steel gantrys with two three phase chain hoists on. they are ip67 rated , but im wandering should the gantry its self be bonded????.. And if so how. The chain hoists are supplied by comando plug and socket that is unpluged when not in use. I think personally the gantry should be bonded but there is nothing in the regs that covers it, and if so how would it be done?? i would have to have a removeable earth bond woulnt i??

 

[Knobhead]

If the gantries are part of a metal structure then no. On the other hand if brick piers support them then I would.

There was no bonding to these

View attachment 12671

 

[Engineer54]

I take it, were not TALKING about the size the gantry crane shown in Tony's photo if the supply is via a commando plug and socket?? Any steelwork that is solidly fixed too, or embedded in to a concrete slab should be earthed, or the steelwork within the slab earthed. the moving section gantry will be earthed via it's steel wheels on the running section steel's.

If your trenching your supply cables to these outside cranes, then run a separate CPC from the MET to connect to the gantry steelwork, or the slab steelwork (if not already earthed or bonded).

 

[Spazz]

The gantry metal work would have to be bonded (steel structure) .
The gantry itself will depend on how it runs across the RSJ - if its on metal rollers (as expected) there is a permanent connection between the metal work of the gantry and RSJ. If the contact points are rubber or another non conducting material then yes it would need to be bonded.
The way you would bond it is the exact same way as you put the power to the hoist in the first place (if its electric powered)

 

[flake]

Its a massive in size you can say, well once me have to cure the wiring for that crane
I tried my best but failed. Its very difficult and tricky. any expert more than me can control this.

 

[ipf]

Its a massive in size you can say, well once me have to cure the wiring for that crane
I tried my best but failed. Its very difficult and tricky. any expert more than me can control this.

Speaking of gantry's, wind me up please.