Earth loop

[sparky147]

just finnished installing 5 x rcd sockets using 4mm cable run 60 meters using a 32amp type c mcb and getting a reading of 1.06 what would be the possible cause of the high reading

 

[Roger]

Hi there,

Why have a C type MCB ,use a B and problem solved.Or make it a ring if its in conduit albeit very long it could be done.

Why RCD sockets ,so if there is a problem it trips at source ? as opposed to walking to the CU to reset trip ?

 

[davelerave]

bring down the required Zs alright


i usually work off breaker size for volt drop on these circuits

dropping about 10v already at 16amp

 

[telectrix]

As far as i know Tel, they all have to comply with the laid down ''common'' characteristics for each type of MCB. So even if there were some sort of difference between manufactures, i doubt if they'll tell you..lol!!!

that's what i thought, but there was a thread on here a while ago suggesting this. as we all know BS7671 is not statutory, would be interesting to see if manufacturers can specify MCBs tripping within recommended times at higher Zs values. obviously i can't condone departing from the brb, but on borderline values the cost of increasing the cable size could lose a job.