Published: 30 June 2008
Category: Q&A
Our Voltimum Experts answer your questions on a daily basis in our Technical Expertise area. This Question of the Day concerns a phase loop test and whether the measured value was correct. It is answered by SELECT:
Question: I conducted a phase loop test on an existing installation and the value I got was 6.7ohms. Is this value low enough to allow a fault current to flow to operate the protective device? If not, what is the acceptable value?
Answer: Depending on the type of protective device, the maximum earth fault loop impedance values should comply with Table 41B2 or 41B1 from BS7671:2001.
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