one of those sodden zs teeth grinding days

the pict · Jul 18, 2016

New 32a C RCBO 4mm T&E radial laundry circuit, in order to take the load off a ring I installed the aforementioned, 5 doubles for dryers, washers and a roller press, 3 washers 2 dryers in total and well under 32a I install a C to deal with any motor start/ stop reverse etc and heaters, top reading is .77 on the end not over by much but it still annoys the hell out of me .58 at the first, end socket is a little roller press a shade over 1500w , So would you drop to a B or leave it as is ?
Pict

Leesparkykent · Jul 18, 2016

the pict said:
New 32a C RCBO 4mm T&E radial laundry circuit, in order to take the load off a ring I installed the aforementioned, 5 doubles for dryers, washers and a roller press, 3 washers 2 dryers in total and well under 32a I install a C to deal with any motor start/ stop reverse etc and heaters, top reading is .77 on the end not over by much but it still annoys the hell out of me .58 at the first, end socket is a little roller press a shade over 1500w , So would you drop to a B or leave it as is ?
Pict

Its covered by a 30mA RCBO 50V/30mA=1667 Ohms. Its not ideal from a design point of view as its a new circuit on TN system but hey I wouldn't be loosing any sleep over it. Its covered by the RCD max Zs value.....

polo1 · Jul 18, 2016

Measured through the RCBO? Or Ze + (R1+R2)?

the pict · Jul 19, 2016

Measured at socket through RCBO

telectrix · Jul 19, 2016

try the alternative hi-current test. short l-e at last socket ( with RCD and MCB OFF ), then measure across RCD Lin and MCB Lout.

[ElectriciansForums.net] one of those sodden zs teeth grinding days

Andy78 · Jul 19, 2016

What is the calculated value of Zs for this circuit ?

HappyHippyDad · Jul 19, 2016

telectrix said:
try the alternative hi-current test. short l-e at last socket ( with RCD and MCB OFF ), then measure across RCD Lin and MCB Lout.

View attachment 32727

You love that diagram Tel!

I think Richard better put a patent on it pretty darn quick

westward10 · Jul 21, 2016

Is that 4.0 T&E surface fixed cos if it ain't it doesn't want to be on a 32A device no matter what religion it is.

telectrix · Jul 21, 2016

westward10 said:
Is that 4.0 T&E surface fixed cos if it ain't it doesn't want to be on a 32A device no matter what religion it is.

buried in a non-insulating wall.e.g. plaster, still counts as ref.method C.

westward10 · Jul 21, 2016

Throughout it's run, from the consumer unit and any cavities?

davesparks · Jul 22, 2016

the pict said:
New 32a C RCBO 4mm T&E radial laundry circuit, in order to take the load off a ring I installed the aforementioned, 5 doubles for dryers, washers and a roller press, 3 washers 2 dryers in total and well under 32a I install a C to deal with any motor start/ stop reverse etc and heaters, top reading is .77 on the end not over by much but it still annoys the hell out of me .58 at the first, end socket is a little roller press a shade over 1500w , So would you drop to a B or leave it as is ?
Pict

Is a C type sufficient to cope with motor inrush? I think it rarely is in practice, but presumably you have actually calculated this rather than guessing?

What did your design calculations come up with for this circuit? Presumably they indicated that it should meet the required Zs which then suggests there is a problem with the circuit.