M
mgumbrell
Supplementary Bonding:-
· Regarding Regulation 415.2.2
o What would be regarding as having satisfied the effectiveness of supplementary equipotential bonding?
§ I understand that the Resistance between simultaneously accessible exposed-conductive-parts on a 230v system (50v being the agreed safe “touch Voltage”) should be calculated at the highest rating of the protection device serving that area; typically 32A. However a fault to earth could happen at any location in an installation. Therefore what (I[SUB]a[/SUB]) should be used to calculate the effectiveness as this may be a sub-main cable causing a fault to earth protected by a MCCB. In short apart from special locations (Part 7) that may define Supplementary Bonding requirements what (I[SUB]a[/SUB]) should be used in the calculation of resistance in formula (R ≤ 50 V/I[SUB]a[/SUB]) Based on:-
· 32A Circuit Breaker the Resistance between simultaneously accessible exposed-conductive-parts should be less than or equal to – 1.563 Ω (Is this correct?)
· 32A 30ma RCBO the Resistance between simultaneously accessible exposed-conductive-parts should be less than or equal to – 1666.667 Ω (Is this correct?)
o However, where there is a mixture of circuits protected by various protective devices; again I am unsure on what protective device rating should be used.
Is anyone able to advise?
Regards
Matt
· Regarding Regulation 415.2.2
o What would be regarding as having satisfied the effectiveness of supplementary equipotential bonding?
§ I understand that the Resistance between simultaneously accessible exposed-conductive-parts on a 230v system (50v being the agreed safe “touch Voltage”) should be calculated at the highest rating of the protection device serving that area; typically 32A. However a fault to earth could happen at any location in an installation. Therefore what (I[SUB]a[/SUB]) should be used to calculate the effectiveness as this may be a sub-main cable causing a fault to earth protected by a MCCB. In short apart from special locations (Part 7) that may define Supplementary Bonding requirements what (I[SUB]a[/SUB]) should be used in the calculation of resistance in formula (R ≤ 50 V/I[SUB]a[/SUB]) Based on:-
· 32A Circuit Breaker the Resistance between simultaneously accessible exposed-conductive-parts should be less than or equal to – 1.563 Ω (Is this correct?)
· 32A 30ma RCBO the Resistance between simultaneously accessible exposed-conductive-parts should be less than or equal to – 1666.667 Ω (Is this correct?)
o However, where there is a mixture of circuits protected by various protective devices; again I am unsure on what protective device rating should be used.
Is anyone able to advise?
Regards
Matt