TT system and earthing

[Des 56]

But if the 3 conditions are satisfied, what do you achieve with the green/yellow everywhere?

All that regulation did was allow a competent person to decide if supplementary connections were necessary based on a sound formula.

The addition of rcd protection is then a step forward.

I cant and wont dis agree with that statement,however,it has become a very common opinion, by myriads of people who perform in the trade, from electricians to plumbers and kitchen fitters, that supplementary bonding is no longer required because there is an Rcd present

The 3 conditions on paper will confirm that supplementary bonding can be ommited,that is if the awareness of those 3 conditions is there in the first place,too much emphasis has been put on the competent individual to make that decision when the question of that competence is suspect in so many other trades operating in this trade ,

 

[IQ Electrical]

I cant and wont dis agree with that statement,however,it has become a very common opinion, by myriads of people who perform in the trade, from electricians to plumbers and kitchen fitters, that supplementary bonding is no longer required because there is an Rcd present

The 3 conditions on paper will confirm that supplementary bonding can be ommited,that is if the awareness of those 3 conditions is there in the first place,too much emphasis has been put on the competent individual to make that decision when the question of that competence is suspect in so many other trades operating in this trade ,

It's that word again and I agree, I often have to explain that it's not just a simple case of 'if there's RCD protection then no supplementary bonding'.

It's not practical though to impose blanket proviso's just because some people can't interpret the regulations, where do you stop?

 

[malcolmsanford]

Des quite agree that some "competant" persons do in fact think that regardless of the 3 conditions then stick an RCD on it and no need for supplementry bonding, and ignore the other 2 parts.

The part about disconnection times will indeed be covered by the RCD, so the RCD additional protection will satisfy 2 parts of regulation 701.415.2. It is though the 3rd part and what it means that these "competant" persons struggle on.

Is it first off an extraneous conductive part, and if it is then is it effectively connected to the MET as in Reg 411.3.1.2 and to prove this you can calculate by testing to Reg 415.2.2.

This is where the "competant" person, fail and IMO that is mainly due to poor education and training that is now being meted out by certain training courses, and by schemes that seem to think that the average kitche fitters and plumbers are competant persons on electrical installtions .