Max Zs For Starlock MCBs

[Matt Thornton]

Hi all, can anyone help me out with the following please,
I need the max Zs for Starlock MCBs as fitted to a Federal Electric Single Phase Consumer unit
40A ???
30A ???
5A ???
Thanks if you can help.

 

[solo2771]

are they not as in the big red book?

 

[Guest123]

Must admit I've never heard of them, nor has google apparently.

Any markings at all on them??? 3871 type 2 etc???

Judging by the 5 and 30A ratings they aren't going to be 60898's, unless retro fit of course.

 

[pevvers]

I'd be guessing they're 3871's too. The max Zs corrected to 80% can be found in the OSG, just multiply it by 1.2 to get your 100% value. Have you looked on the sides of the MCB, sometimes they have the standard details embossed on there.

 

[Matt Thornton]

Hi Guys, Nothing in the big red book (trust me I've looked!) the MCBs are NOT marked with any thing !. These are NOT BS3871, there is no BS marking at all !. These are at about 50 years old, please don't say change them, i'm just doing a periodic and need the max ZS as Amtech don't do max ZS Values for obsolete MCBs. Thanks anyway.......unless someone knows ?????

 

[Guest123]

Matt they are STABLOK MCB's you have not starlock.....the penny has just dropped.




Anything like this????

 

[Matt Thornton]

Very similar, but not exactly, no red marking on MCBs, could of worn off over the years though, these were in a Federal Electric CU. Any idea of a max Zs ??

 

[pevvers]

These are at about 50 years old

Did they even have MCB's 50 years ago? I know my parents place was build in the late 70's and they still had BS3036 rewireables...

I'm still reckoning that they're BS3871, as I don't know of any other old standard, and some of the manufacturers didn't put the details on them, but the type was marked by different coloured levers on them. I think it's the old Crabtree or maybe the Dorman Smiths that used to be like that.

Try here: -

mcbfinder.co.uk:: Online shopping from Namesco

Some more info from a thread from another forum: -

IIRC it is only the older devices in black casings that have the coloured levers, and the colour gives the type away, black lever is type 4, orange is type 3, green is type 2 and white is type 1 (I've never seen a type 1!)

From: - IET Forums - Stab lok mcb's

Definitely 3871s.

 

[Matt Thornton]

Thanks pevers, I think you have answered my question. Cheers, still think about 50 years or maybe 40 it did have VIR cables before rewiring by others