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Topic Title: Zs reading on ground source heat pump
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Created On: 27 August 2011 07:34 AM
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 27 August 2011 07:34 AM
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jonah71

Posts: 41
Joined: 05 March 2006

Test readings on ground source heat pump are showing R1 + R2 as 0.03 ohms, zs reading taken at rotary isolator for the pump is 0.27 ohms. Protective device is a 63A type d mcb, run of cable is approx 7 metres, wired in 16mm t & e, ze is 0.11 ohms, max for a type d is 0.15 ohms so i'm well over but how come given all the other readings. Advice needed please
 27 August 2011 08:00 AM
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dickllewellyn

Posts: 1150
Joined: 19 March 2010

What tester have you used, and on what setting? Is there an associated RCD on the circuit?

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Richard (Dick)

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 27 August 2011 09:08 AM
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aligarjon

Posts: 2866
Joined: 09 September 2005

calculate your zs from your r1 + r2 reading.
the quality of your lead connection and the accuracy of your meter can affect the readings quite a lot, especially if its through an rcd. ( the last one i did had to have a 100m/a rcd on it ) .

Gary

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