Main switches at residential property
Posted: Tue Apr 14, 2020 12:59 pm
Hi Guys - just a question about main switches and overcurrent protection of mains at a residential property. I have asked some of the guys I work with but don’t totally trust their answers.
1) How do you know the fuse size that has been used by supply authorities before the meter box? The company I work at maximum demand done by limitation often seems to assume this is 63 amps, is this a standard size or is it a dangerous assumption being made?
2) Is there a reason that main switches are used instead of a 63 amp (or suitable) MCB? Is it something to do with a main switch being double pole operating in the supply and hot water single core? A single pole MCB may not be able to achieve this as by not isolating the hot water single it does not “isolate the supply of electricity to the electrical installation” as per 1.4.82?
Thanks
1) How do you know the fuse size that has been used by supply authorities before the meter box? The company I work at maximum demand done by limitation often seems to assume this is 63 amps, is this a standard size or is it a dangerous assumption being made?
2) Is there a reason that main switches are used instead of a 63 amp (or suitable) MCB? Is it something to do with a main switch being double pole operating in the supply and hot water single core? A single pole MCB may not be able to achieve this as by not isolating the hot water single it does not “isolate the supply of electricity to the electrical installation” as per 1.4.82?
Thanks