rcd not tripping

[matt12321]

looking for a fault on a caravan where the rcd trips when a main earth is added. with no main earth the rcd want trip. the caravan has only got an earth path via bonding from the earth rod to the db and no main earth from the earth rod to the db.

zs is 66.4 on sockets 67 on lights and 66 on the shower.

the board has been tested and no faults found. as soon as u add 4mm or a 10mm main earth the rcd trips when say the cooker or shower are turned on.

 

[gamblor6]

when an rcd trips it usually is because there is an ir fault, ie l-n l-e n-e. or high current in the earth from computers, 6 or more on one circuit ish, ITS A PROBLEM IN THE INSULATION. it might be as small as a fixing screw nicked a neutral, open everything and check.

 

[london_uk]

when an rcd trips it usually is because there is an ir fault, ie l-n l-e n-e. or high current in the earth from computers, 6 or more on one circuit ish, ITS A PROBLEM IN THE INSULATION. it might be as small as a fixing screw nicked a neutral, open everything and check.

I think you might be right, myself I would bypass 1st RCD and the meter for a test and install a secondary RCD in the right place

 

[gamblor6]

no need for secodary rcd, , not got much exp of caravan parks but a 2 min check on ir will show this problem.

 

[london_uk]

just for a test

however, it can be illegal to bypass

 

[matt12321]

correct

 

[topquark]

some of you are are so good that I am afraid to say my opinion in case I am wrong and had few drinks now.

I don't think RCDs are designed to be installed before the meter, the interference could be the problem .

Just wade in mate, we're all trying to help. Even if it's wrong (I am frequently) it may jog someone else's memory and we find a solution.

 

[topquark]

Another afterthought. The meters at each van are often owned by the caravan site (not the DNO) and are used to work out what to charge each van. The main meter to the site is what the park gets charged for and they then apportion the costs to each van.

 

[gamblor6]

Just wade in mate, we're all trying to help. Even if it's wrong (I am frequently) it may jog someone else's memory and we find a solution.

my thoughts exactly, im often wrong too, its a learning curve for us all. sometimes im even right lol.