Reading Richard Harts post, I had to take a breath before posting this response, if Hager are going around telling potential customers that they ‘we have to fit them on every job we touch’. Well that is just misleading and down right wrong, if anything, manufacturers should refer to the Wiring Regulations and give a clear explanation of how to carry out a CRL along with explaining Table 443.2 and the associated Annex A443 the examples of calculated risk level for the use of SPD’s. Then dropping back to Reg 443.4 and going into detail the paragraph following indent iv, referring to single swelling units. Not forgetting all the other associated Regs for SPD’s.
Hopefully at the next AESM meeting perhaps someone from the IET could have a session on SPD’s I say that as ever since the introduction of the 18th I have heard and seen so much misinformation on the subject and I’m not in anyway saying I understand them in entirety. I can see the introduction of SPD’s by stealth and by the 2nd Amd (or maybe even the 1st which is being worked on) of the 18th everyone will say install or you are not fit for purpose. By the way, even doing the CRL calculation can give you a headache as distances are never truly given by the network operators. (Deep breath now and calm 🙂 By the way don’t even start reading the Notes of Reg 443.1.1 as these will tie you up in knots and lead to an even longer discussion as overvoltages are not just purely of atmospheric origin!