Main Fuse Confused ?

[waitees]

Hi just writing a cert and got to the main fuse.

The main fuse has written on it isco, series 3 ?

but does not say which type or its short circuit capacity, anyone any ideas ?

also got my assesment tomo.

Im sound with testing, just maybe with if he throws me with a problem question, if i take a r1 & r2 plus my ze = zs, and then i do a live direct zs test and get two different answer what could potentially be the problem ?

thanks for all the support in the past questions !

 

[Sintra]

Im sound with testing, just maybe with if he throws me with a problem question, if i take a r1 & r2 plus my ze = zs, and then i do a live direct zs test and get two different answer what could potentially be the problem ?

thanks for all the support in the past questions !

If you calculate your Zs by adding R1 + R2 to Ze you will probably get a higher figure than if you measure the Zs directly.
This is because you introduce parallel earth paths when measuring Zs live.
ie all bonding in place.

 

[pevvers]

The main fuse has written on it isco, series 3 ?

but does not say which type or its short circuit capacity, anyone any ideas ?

Chances are it's a BS1361 IIb, which has a short circuit capacity of 16.5kA...

 

[acat]

As above put 16.5 in and when it comes to the fuse put either lim or 60/80 that way you are telling people you have not broken the seal and looked at the main fuse

Hope that helps and good luck tomorrow let us know how you got on.



Chris