32A mcb supplying 32A 30ma rcd unit next to db

[Guest112]

Hi as title says my engineer wants me to fit the above to protect ring circuits supplied from a crabtree c50 board, wants me to supply a rcd unit from a 32A mcb with 4mm singles and then supply the ring from the 32A 30ma rcd,

I think the reason for doing this is either you cant get crabtree c50 rcbos anymore OR its cheaper to buy and fit the rcd unit OR theres no room in the board as im pretty sure the old crabtree rcbos take up 2 ways in the board.

What are you opinions about this method and before you say the local council wont fork out the money for db change, my concern is the discrimination between the mcb and rcd both being 32A but being that the rcd will be fitted next to the board is this a problem? obviously i will label the rcd unit with the relevant circuit information, install rcd sticker on the board if there isnt one and update the circuit information on the db schedule,

I dont particularly agree with this method as in my opinion is that the council are just putting off the inevitable of changing the db,

can you see anything wrong with this? thanks in advance

 

[telectrix]

your 32A rating for the RCD is the max. rated current. not overload, so your \RCD will trip on an earth fault and the 32A MCB on an overload. no problem.

 

[Guest112]

brilliant i was wondering about the 32A rating of the rcd i didnt think this was overload protection so as you said its the maximum rated current of the device so happy days, so aslong as the device is supplied from a protective devide 32A or less there shouldnt be anything wrong with it, thanks tele

 

[Deleted member 26818]

Will 4mm² singles have sufficient current carrying-capacity?

 

[telectrix]

for the short length fron MCB to RCD , i would think so,it's used in 32A radial circuits.but i personally would use 6mm ( partly as i always have a few offcuts of 6mmm T/E lying about)

 

[clicon357]

Hi as title says my engineer wants me to fit the above to protect ring circuits supplied from a crabtree c50 board, wants me to supply a rcd unit from a 32A mcb with 4mm singles and then supply the ring from the 32A 30ma rcd,

I think the reason for doing this is either you cant get crabtree c50 rcbos anymore OR its cheaper to buy and fit the rcd unit OR theres no room in the board as im pretty sure the old crabtree rcbos take up 2 ways in the board.

What are you opinions about this method and before you say the local council wont fork out the money for db change, my concern is the discrimination between the mcb and rcd both being 32A but being that the rcd will be fitted next to the board is this a problem? obviously i will label the rcd unit with the relevant circuit information, install rcd sticker on the board if there isnt one and update the circuit information on the db schedule,

I dont particularly agree with this method as in my opinion is that the council are just putting off the inevitable of changing the db,

can you see anything wrong with this? thanks in advance

You can get seconhand c50 stuff here:

Electrical Wholesale Retail Supplies including Gewiss Sockets and Switches, Minature Circuit Breaker and Surface Mounted Sockets