Earth bonding

[PhilT74]

Hopefully an easy question for somebody! If you had a sizable Aluminium framework with a small number of 230v lamps attached via plastic clamps, but the supply cables were tied to this framework, would you need to earth bond the framework? Or would an RCD on the supply lines suffice?

 

[Lewish]

That is a question that is best answered by checking the code of the country you are located in. You didn't specify where you are located.

 

[PhilT74]

Sorry, I am in the UK.

 

[Lewish]

Hmm, sorry pal, I am on the other side of the fish bowl called the Atlantic. Perhaps someone else can help.

 

[BrianR]

I believe you would need to ground the aluminium structure. It is not a double insulated installation and could become live in the event of a failure or damage. I do not believe that the ELB would remove the need for grounding.

 

[ccaserta]

It depends on the type of supply wire, if the power cord is standard reinforced cable like on lights in your house, bonding is not required. If it is single insulation and a single fault would result in hazardous live voltages touching metal, then it must be bonded.

Normal pwer cords provide the insulation nned to protect persons form electrical shock in case of a single fault. However if metal supports conductors used meeting only basic insulation additional grounding is required. It is also necessary to run the wire in metal conduit if it is only basic insulation. Christopher Caserta
ccaserta@us.tuv.com
Ph:904-225-0360

 

[TrickyDickS]

In the uk except for soom special situations the IEE Reg require that all exposed metal work is bonded to the earth system. This to ensure that no voltage difference can be present between any exposed conductive surfaces. If the structure is outside it would also require an RCD.

 

[BrianR]

It's the same in Australia. General power outlets have an RCD and all exposed metal must be grounded. My experience is that the failure modes are more likely to result from contamination or damage to the electrical fittings than from cable insulation failure.

 

[STUONTIPS]

Yep agree with trickydicks 100%, just been though this process in UK factory

 

[xyzz]

But what's a big deal to ground it?

 

[towheedm]

I agree with xyzz, you have nothing to lose by grounding it.

 

[DCElectrical]

I agree with brianR and in addition its a good idea to earth bond the metallic framework. In case of fault current situation, by bonding the earth frame, the fault current will follow through the Earth Fault loop (low impedence loop), thus tripping the Circuit breaker if used in MEN system. In absence of earth bonding the fault current will flow through the person in contact of the frame. Due to high impedence of our body, the circuit breaker may not trip.