BS Codes

Duncan Bennett · Jun 5, 2012

Am I correct in saying that a 6a, type 2 MCB is BS 3871, and can anyone tell me where I'd get a definitive list of BS Codes respective to there 'type'.

This stuff drives me nuts!:mad2:

Thanks.

Richard Burns · Jun 5, 2012

YesType 1,2, and 3 will likely be BS3871
Type B,C,D will likely be BS60898
This pdf courtesy of Lenny may assist.
The types of CB and their types and trip characteristics are listed on page 9.
View attachment Beama guide to low voltage circuit breakers.pdf

Silly Sausage · Jun 5, 2012

Appendix 1 in BRB lists lots of the relevant BS numbers relevant to Electrical Installation.
eg BS 88, top of the list(!) for certain fuses. You'll have to read through the list to find the numbers for other protective devices. If you're ultra keen, you can buy them from the BSI shop, at enormous expense!!! BSI Shop - Buy British Standards

Duncan Bennett · Jun 5, 2012

Richard Burns said:
YesType 1,2, and 3 will likely be BS3871
Type B,C,D will likely be BS60898
This pdf courtesy of Lenny may assist.
The types of CB and their types and trip characteristics are listed on page 9.
View attachment 12770

Thanks Richard.
I'd thought that was the case, but sometimes the more you read the less you take in, and I was getting info. log jammed :-(

Duncan Bennett · Jun 5, 2012

Archy Styrigg said:
Appendix 1 in BRB lists lots of the relevant BS numbers relevant to Electrical Installation.
eg BS 88, top of the list(!) for certain fuses. You'll have to read through the list to find the numbers for other protective devices. If you're ultra keen, you can buy them from the BSI shop, at enormous expense!!! BSI Shop - Buy British Standards

Cheers, Archy.

I got it nailed down in the end.
Just checked the BS7671 and the 3871 isn't even listed there anymore! Time rolls on :-(

telectrix · Jun 5, 2012

Duncan Bennett said:
Cheers, Archy.

I got it nailed down in the end.
Just checked the BS7671 and the 3871 isn't even listed there anymore! Time rolls on :-(

time to dig out the old 16th regs. and they're in the 16th OSG.

Silly Sausage · Jun 5, 2012

I've got the Z esses for 3871s if you need them. Old brown 2004 OSG values.

here...

netblindpaul · Jun 5, 2012

Archy,
Are these 230 or 240 V values?...

Silly Sausage · Jun 5, 2012

I have noticed that Zs values seem to be different from old to new regs. (need to get out more)

Thanks Paul!, looked in the BBB and Uo seems to be 230.
Chit Chat forum only now

Duncan Bennett · Jun 6, 2012

Archy Styrigg said:
I've got the Z esses for 3871s if you need them. Old brown 2004 OSG values.

here...

View attachment 12771

Many thanks, Archie.

netblindpaul · Jun 6, 2012

Archy Styrigg said:
I have noticed that Zs values seem to be different from old to new regs. (need to get out more)

Thanks Paul!, looked in the BBB and Uo seems to be 230.
Chit Chat forum only now

Sorry Archy, just dipped back into this thread and realised no smiley, sorry!
There should have been a

at the end of my post.

dwardy · Jun 8, 2012

if its a bs 60898 it will be a letter eg b,c or d
if its a bs 3871 it will be a letter eg 2 or 3

netblindpaul · Jun 8, 2012

Not true dwardy,
BS3871 had B,C & D integrated into it before BS EN 60898 was issued.
Trust me, sorry, I am sad enough to have a copy of the last revision of BS3871!

Silly Sausage · Jun 8, 2012

netblindpaul said:
Sorry Archy, just dipped back into this thread and realised no smiley, sorry!
There should have been a at the end of my post.

I must have something, never mind!

Does it matter whether they are 230 or 240?
Something is nigglying me in the darkest recesses of my brain though.

netblindpaul · Jun 8, 2012

Yes Archy, it does "actually" matter in the "absolute" sense, but IMHO if you are flying that close to the wind with your Zs values then you should be triple checking things anyway.
I have actually been that close with Zs's & virtually nothing economically viable could be done.
Not a nice feeling TBH.

Have a think and see what you come up with.

johnboy6083 · Jun 8, 2012

It will matter as paul said, when close to limits, as the higher the voltage, the lower the current required to make the device trip, and the higher the Zs value allowed.
This is from the formula: If= Uo/Zs
Please correct if I'm on the wrong lines Paul.

Silly Sausage · Jun 8, 2012

netblindpaul said:
Have a think and see what you come up with.

Not tonight!

I'll open myself up for a total flaming here, I can be quite blasé (within reason) when it comes to measured Zs values, but more of that later!

Duncan Bennett · Jun 8, 2012

Guys, I'm overwhelmed

Silly Sausage · Jun 8, 2012

johnboy6083 said:
It will matter as paul said, when close to limits, as the higher the voltage, the lower the current required to make the device trip, and the higher the Zs value allowed.
This is from the formula: If= Uo/Zs
Please correct if I'm on the wrong lines Paul.

Not quite, I think, Paul will put us right.
Breaker trips at a certain current, so to achieve that current, if Uo is lower, the Zs will have to be lower.

Explain this to me fellas...

Brown book Z esses