Bonding concrete rebar do you need too?

Hi Andy,


What's your though with respect to "Bonding concrete rebar do you need too"?

It's usually not necessary (at least from a BS 7671 point of view - lightning protection considerations might differ) - most modern habitable buildings in the UK will have a damp proof membrane of some kind between the structural slab and the internal floor surface (to comply with building regulations) - which effectively insulates the floor from the slab - thus the floor isn't an extraneous-conductive-part (as least as far as the internal electrical installation is concerned). There may be contact between the slab rebar and above-ground metalwork (either deliberate or fortuitous) but above ground bonding takes care of that. Also UK builders also know nothing about earthing or bonding, so by the time the electrician arrives on site there's usually several inches of solid concrete in the way of any possible connection point, unless the whole project is better managed than usual.


BS 7671 does demand re-bar bonding in a few special situations - concrete floored animal housing for example (section 705) - but these are very much regarded as special cases rather than the norm and deal with a much more demanding situation - from 'long wheel base' animals being far more vulnerable to shock from differing potentials to the presence of large amount of, ahem, 'organic fluids', that can make the concrete much more conductive.


   - Andy.

Hi Andy,


What's your though with respect to "Bonding concrete rebar do you need too"?

It's usually not necessary (at least from a BS 7671 point of view - lightning protection considerations might differ) - most modern habitable buildings in the UK will have a damp proof membrane of some kind between the structural slab and the internal floor surface (to comply with building regulations) - which effectively insulates the floor from the slab - thus the floor isn't an extraneous-conductive-part (as least as far as the internal electrical installation is concerned). There may be contact between the slab rebar and above-ground metalwork (either deliberate or fortuitous) but above ground bonding takes care of that. Also UK builders also know nothing about earthing or bonding, so by the time the electrician arrives on site there's usually several inches of solid concrete in the way of any possible connection point, unless the whole project is better managed than usual.


BS 7671 does demand re-bar bonding in a few special situations - concrete floored animal housing for example (section 705) - but these are very much regarded as special cases rather than the norm and deal with a much more demanding situation - from 'long wheel base' animals being far more vulnerable to shock from differing potentials to the presence of large amount of, ahem, 'organic fluids', that can make the concrete much more conductive.


   - Andy.