I've recently installed a shower circuit for someone but when i come to test i can't seem to get the zs value for my showere below 1.79, which i no is high, the shower is on an rcbo i just need to no what i can do to get the value down and why this could be happening.
High zs on shwoer circuit
- Thread starter bobsmate
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What is the prospective fault current reading? With a RCD the to earth value is not so important but if for example a B40 MCB is used then 200A needs to flow to open it using the magnetic part of the trip (5 x 40) so if the PFC exceeds 200 you are OK.
What is Ze could that be problem? and how much cable is used? and does it go through any switches or junction boxes which could raise the reading through a bad connection.
The reading you give seems too low for TT system and too high for TN-C-S but could be correct for TN-S so what sort of supply do you have?
What is Ze could that be problem? and how much cable is used? and does it go through any switches or junction boxes which could raise the reading through a bad connection.
The reading you give seems too low for TT system and too high for TN-C-S but could be correct for TN-S so what sort of supply do you have?
What type of earthing system is present ? Have you measured Ze ?
What size cable have you used and how long is the run ?
Are all connections sound and isolator switch in good order ?
What size cable have you used and how long is the run ?
Are all connections sound and isolator switch in good order ?
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0.64 is within the allowed range, but it still seems very high.
A 20m length of 10mm T+E should have a R1R2 value of about 0.13,
so with a Ze or 0.24,
Zs should be around 0.37 or so - the measured value could well be less due to parallel earth paths etc. Certainly not anywhere near 0.64
As you have measured before and got a much higher value, it suggests a loose connection somewhere.
A 20m length of 10mm T+E should have a R1R2 value of about 0.13,
so with a Ze or 0.24,
Zs should be around 0.37 or so - the measured value could well be less due to parallel earth paths etc. Certainly not anywhere near 0.64
As you have measured before and got a much higher value, it suggests a loose connection somewhere.
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