commercial building

[soulman]

my friend has just purchased a commercial building i had a quick peek at the electrics. i was surprised to find 3 consumer units, two were 1361 cartridge fuses the other was 3036 board these were fed from a db with old mem porcelain fuses with fuse wire linked across them. my first question, is it acceptable to use a 3036 board in commercial premises and i noticed that two banks of 10 fluroscent light were ran from a 15a 3036 fuse had should they not be on a 5 or this because of the surge when switching them on. cheers (please note still learning just in my third year)

 

[sellers]

no problem with 3036's you'll find them in a lot of commerical buildings and as for the 15a as long as the cable calcs work out its no problem, cable size, installation method, etc

 

[Doc Hudson]

What is your reasoning or regulations that make you feel 3036's are not acceptable Soulman? Many people seem to have ideas that if its not an MCB of some sort its unsafe? I'd be interested to hear if this is taught or passed on knowledge from other electricians.

Doc H.

 

[soulman]

hi it was something that was mentioned at college with regards to the new regs, coming out in june i,ve probably got the wrong end of the stick. Also the cable size was 1.5 and clipped direct and know this can take upto about 19amps. but i would have thought a 5 amp to be more appropriate

cheers lads

 

[Sidewinder]

Soulman,

3036's ares still in the 17th thus you can still install them.

as above just because it is not an mcb does not make it against the regs

 

[sellers]

also if the cable can take 19amps then there is absolutley no difference in safety between a 5amp fuse and a 15amp fuse, as long as the circuit meets the required zs

 

[waynehayes]

When I was at college, our tutor was of the opinion that 3036's were fine apart from the relatively low breaking capacity.

 

[Sidewinder]

wayne,

An enlightened tutor you had!

None of us can comment on the breaking capacity as we are not party to that info.

 

[waynehayes]

wayne,An enlightened tutor you had!

None of us can comment on the breaking capacity as we are not party to that info.

He liked to think he was most enlightened and that at anything over 4kA (max) would spew molten metal over an unsuspecting granny trying to replace the wire on her blown fuse. He was also an advocate of 10mA RCBO's!

 

[steptoe]

He may well be right, though some 3036 are rated at 1ka !

 

[batty]

He may well be right, though some 3036 are rated at 1ka !

Wylex rewireables are rated at 1ka its only the ceramic types that are larger ka rated and a lot of them have the asbestos pads which is not so good. This may be of help to those learning the trade.

 

[PC Electrics]

also if the cable can take 19amps then there is absolutley no difference in safety between a 5amp fuse and a 15amp fuse, as long as the circuit meets the required zs

Sorry to pick you up on this Sell, but you're forgetting the derating factor of 0.725 that should be used for 3036s. This drops the ccc of the cable from 19A to 13.7A. So, strictly speaking, 1.5 on a 15A 3036 does not comply, even clipped direct.