H
honest jon!
Just been to look at job tonight in a commercial kitchen where they are experiencing nuisance rcd tripping.
Bare with me while i explain the scenario!
A separate/outside food store and prep room has approx 5 large fridges/freezers, lights, insectocutor, and a small computer printer for orders. This has its own 30ma rcd protected board. Fed in swa with divorced earth. Earth rod only has small (approx 4 mm2) main earth conductor.
This is fed from the 3 phase board in the kitchen which does EVERYTHING in the kitchen – lights, skts, cookers, ovens, extract fans etc etc.... Original sparkatricians decided on the easiest option to ensure compliance with 17[SUP]th[/SUP] ed – a 3 phase 30ma RCD main switch.
When (Brand new & IR tested ok) computer printer is plugged in in the store sockets the rcd on the 3 phase board trips. I dont have an earth leakage clamp meter but fairly positive its just an obvious problem of cumulative earth leakages (in both kitchen and store) from fridges, ovens etc. RCD ramp tests = 24ma so no sensitivity issues.
Owner wants this computer printer to work in this store/prep area as this is a remote printer for food orders from restaurant staff to kitchen prep staff.
Obviously submain could be fed without rcd protection as is in swa, but unable to do this with rcd main switch on 3p board. Cant replace rcd with main switch and rcbo’s on skt circuits as other ccts would not then meet regs (cables buried in walls<50mm). At £35 a pop owner wont want a 8 way 3p board full of rcbo’s!!!
Only other options i can see is to pull new sub main in from origin of supply to building (not sure where that is at mo so unsure about cost and how realistic this option is yet as old building and route may not be feasible without major disruption), or alternatively take a feed out bottom of 3p rcd, through side of db into an adaptable box and put these tails through correct rated mcb to feed store rcd board...providing doubled up tails will fit in bottom of rcd main switch.
Any thoughts of a solution???
Bare with me while i explain the scenario!
A separate/outside food store and prep room has approx 5 large fridges/freezers, lights, insectocutor, and a small computer printer for orders. This has its own 30ma rcd protected board. Fed in swa with divorced earth. Earth rod only has small (approx 4 mm2) main earth conductor.
This is fed from the 3 phase board in the kitchen which does EVERYTHING in the kitchen – lights, skts, cookers, ovens, extract fans etc etc.... Original sparkatricians decided on the easiest option to ensure compliance with 17[SUP]th[/SUP] ed – a 3 phase 30ma RCD main switch.
When (Brand new & IR tested ok) computer printer is plugged in in the store sockets the rcd on the 3 phase board trips. I dont have an earth leakage clamp meter but fairly positive its just an obvious problem of cumulative earth leakages (in both kitchen and store) from fridges, ovens etc. RCD ramp tests = 24ma so no sensitivity issues.
Owner wants this computer printer to work in this store/prep area as this is a remote printer for food orders from restaurant staff to kitchen prep staff.
Obviously submain could be fed without rcd protection as is in swa, but unable to do this with rcd main switch on 3p board. Cant replace rcd with main switch and rcbo’s on skt circuits as other ccts would not then meet regs (cables buried in walls<50mm). At £35 a pop owner wont want a 8 way 3p board full of rcbo’s!!!
Only other options i can see is to pull new sub main in from origin of supply to building (not sure where that is at mo so unsure about cost and how realistic this option is yet as old building and route may not be feasible without major disruption), or alternatively take a feed out bottom of 3p rcd, through side of db into an adaptable box and put these tails through correct rated mcb to feed store rcd board...providing doubled up tails will fit in bottom of rcd main switch.
Any thoughts of a solution???
