The post was written again to provide the OP with the information to understand what is going on, not as an instruction to do it a particular way. 1mm2 flex has a Mv/A/M of 46. assuming a fault current of 6Amps required to pop a 3Amp fuse to a boiler it is a voltage drop of 2.5Volts over a 9 metre length. Normal operation as you said "Its a boiler not a welder" will be well bellow 3Amps.
there are some strange rules on flex under pat rules lengths are limited unless an rcd plug is fitted then the other crazy one is use 0.75mm for over 6amps thats fine if it has molded plug and (where used, like a iec socket) a moulded socket rules say thats ok wtf
Sorry Fire but the EU has nothing to do with it. This is the Code of Practice for In-service Test and Inspection and is wirtten by the IET. Tina the rules are there because the document applies to appliances and extension leads, not fixed domestic wiring. You can't terminate 4mm2 cable in a 13 amp plug, it won't fit! So lengths have to be restricted. If you do the calculations it all makes sense. Kind regards
yea know they mean it for standard plugs just dont get how they allow 0.75mm for over 6amp power demand and fusing
Because BS 1363 allows for manufacturer's flex less than 2m in length and has a csa of 0.75mm and is fitted with a non-rewirable plug, it may be used at 10A and be fused to 13A.
same **** different use and i have seen some well over 2 meters with moulded ends and using 0.75mm and fused at 13amp on a steam press (think of an iron that does not move)
hence my dislike and distaste but what can you do rules are rules and heck makes me more work (that i dont mind) i do checks on them every 6 months for just a call out fee (no test charge)
Flex is just flexible wire, The moulded plug argument is because a fitted plug uses screws while a moulded plug does not clamp the core down with a screw. Maintenance maintenance free bla bla bla bla. There is very little room for error on a moulded plug because it would have been fully tested at the factory. Same **** of the public can not be trusted to wire a 3 pin plug. That said the amount i have thrown away over the years for being faulty or even fake is beyond a joke. The new problem that has arisen from moulded flex leads is the amount of fakes it has enabled and i not talking fakes as in brand name labelling i mean labelled as 6Amp or 10Amp 0.75mm2 or 1mm2 and they barely are 0.5mm2 in most cases. Very dangerous fake leads. I was trained to chuck it in the scrap when found years ago and replace with a known real one, probably better before you chuck it to snip of the plug and take a look see if it is or not before you chuck it, that way if you bought a bulk of them you know all of them are junk. and well urm... No Screwfix don't sell these fuses, well not yet anyway lol.
dont worry any i found that dont meet the min standard are disposed of (usually in a sea of holly fire by the god of hell fire a big insinarator (sorry poor spelling) if 0.5mm then cable saved (if all colours pass and pass a pat run) however moulded parts get hell fired)