BREAKING CAPACITY OF BS3036 FUSES

[choccy]

Hi folks testing 2 boards today and I have some Wylex 3036 fuses and some porcelin MEM 3036 fuses but there is no indication of the KA rating of these. Can anyone help?

The pfc is 3.7KA so thinking of changing to the plug in breakers I am sure they are 6KA rated.

 

[Andy™]

3036 are usually 1 or 2KA rated. iirc, wylex plug in are 3KA

providing there is something in the circuit what can break the PFC (service fuse), you dont need to change the 3036's to something that can take the PFC

 

[m4tty]

+1 what Andy says but bs3036s can be 1,2 or 4kA. In gn3 it states s1a is 1kA, s2a is 2kA rated and s4a is 4kA rated. Couldn't help knowing which is Which but I'm sure someone else will be able to help you mate.

 

[m4tty]

But then again it won't really matter as the service fuse will be bs1361 or bs88 so they can withstand 16.5kA minimum so all will be ok?

 

[Chr!s]

providing there is something in the circuit what can break the PFC (service fuse), you dont need to change the 3036's to something that can take the PFC

Thats not necessarily the case Andy.

 

[m4tty]

Thats not necessarily the case Andy.

Why's that then chris, I thought it was ok too? Cheers

 

[a1spark]

Why's that then chris, I thought it was ok too? Cheers

is it not also a requirement that the consumer unit is to bs 60439-3

a1spark

 

[Nicky Tesla]

So why do we need to bother even looking at the mcbs etc?, all we need to know is the the service fuse rating in that case. Carn't see that being right. eg why bother fitting 10k mcbs in 3p boards instead of 6?

 

[Chr!s]

So why do we need to bother even looking at the mcbs etc?, all we need to know is the the service fuse rating in that case. Carn't see that being right. eg why bother fitting 10k mcbs in 3p boards instead of 6?

Well the simple fact is that it isnt right

 

[choccy]

think the outcome will be plug in breakers if i can get them to be above the 3.7ka thanks:Y

 

[monkey5]

think the outcome will be plug in breakers if i can get them to be above the 3.7ka thanks:Y

think they only come in 3kA

http://www.screwfix.com/prods/87979/Electrical-Supplies/Consumer-Units/Wylex-MCBs-Incomers/WYLEX-32A-SP-Type-B-Curve-MCB

wayne

 

[Andy™]

So why do we need to bother even looking at the mcbs etc?, all we need to know is the the service fuse rating in that case. Carn't see that being right. eg why bother fitting 10k mcbs in 3p boards instead of 6?

it would be best to have all devices capable of breakig full PFC, but it some cases, that isnt always possible, so providing you have some device what can, others can be lower.

take a house with TNCS fed from a transformer next door. PFC may well be over 10KA. would you fit the house with MCCB's just to break the fault current or use a normal board with 6KA MCB's and use the service fuse to break the full fault current (if there was a fault that would cause the full PFC)

 

[sparkytim]

BRB Pg 116 536.1

A 100 Amp BS1361 TYPE 2 Fuse rated with 33 KA breaking capacity fitted in service cut-out is deemed to provide back up protection for 16 KA max fault

as deemed max fault at supply point by DNOs.