Published:
13 September 2017
Category:
Q&A
A Voltimum user is uncertain about a Ze test point. ECA has the answer!
This Q & A is one of thousands posted in our Technical Expertise area, and answered on a daily basis by our Voltimum Experts.
Question:
Viewed a job this morning that has old ELCB installed on two tariff supply. From which point do you test Ze on this old installation? They will be replaced asap.
Answer:
Gary Parker - ECA
Good day, thanks for this.
Normally you would measure the external impedance from as close to the origin as possible, possibly the live side of the ELCB or something feeding it, and with the green probe on the earth, be it a TN or TT system. It doesn't seem that the cables are particularly long so the additional impedance in the lives would be very little.