BS4293

[fattony]

I went to look at a small job today just adding a couple of sockets in a office but when I looked at the DB it was populated with BS4293 devices, I initially thought these were old RCBO's, there was a 30 printed on the switch itself, but Ive since done some searching and it seems BS 4293 were replaced with BS EN 61008 but isnt that just an RCD so would the correct BS be BS EN 61009 1 RCB0s?

This is a link to a picture of the device

http://cgi.ebay.co.uk/FEDERAL-GFI30...Breakers_RL&hash=item2560cd78f0#ht_500wt_1156

Has anyone worked with these recently and could shed some light?

 

[RF Lighting]

If they are BS4293 devices then that is the correct BS number.

What do you need the BS number for? Is it just for your certificate, or so you can look up the tripping characteristics etc?

 

[RF Lighting]

As a side note, federal boards are horrible. I also seem to remember there being an issue with old federal circuit breakers not actually tripping on overcurrent.

 

[fattony]

Thanks, it will be for the certificate, I hadnt seen those devices before so planning ahead I wanted to check Zs values, it was a BS 4293 so I'll look up the value for a BS EN 61008.

They look quite old lol

 

[ricicle]

I have got the data for Federal Stablocks somewhere if you get stuck

 

[fattony]

Thanks, I think I am stuck, looked through the big red book and it lists values for 230v 30mA which is 1667ohm but I believe the 30 on the switch indicates its 30A 30mA or am I missing something really obvious here, never seen these before!

 

[RF Lighting]

You should put the actual BS number of the device on your certificate.

IIRC those circuit breakers do not contain a magnetic trip, they are thermal only.

You could try and contact them to see if they still have any technicqal data for these old breakers.

FEDERAL ELECTRIC LTD

FORDHOUSE ROAD, BUSHBURY
WV10 9ED WOLVERHAMPTON , WEST MIDLANDS

Phone : 01902 303300

Guess what? They are now owned by schneider, so good luck.

The 30 on the lever relates to their rated current. The RCD rating will be on a sticker somewhere (which may have fallen off by now)

OOI, did you try and RCD test these devices?

 

[fattony]

Not yet I didnt, but will do when I do the job, do they fail often then?

Its not the BS number I was questioning its the max Zs value, they're not listed in BS7671 - that I can see so I may have to contact the above details, thanks

 

[RF Lighting]

I'm not sure about their failure rate. I've never actually seen a federal RCBO in service!! But given their age, I'd definately be testing it before working on the circuit.

I think being very nice to Mr Ricicle is your best hope of finding out the max permitted Zs for these devices

 

[fattony]

Have to agree with you there, Mr Ricicle would you be able to have a look for the data sheet please?

RF sound advice as always

 

[ricicle]

Will try and remember tomorrow

 

[Adam_151]

As far as I know those RCBOS belonged with the first generation of federal boards and mcbs, going by the none renard series ratings, 30 as opposed to 32, although they were around for a while and its normal to see a 30A 4293 & 3871 rcbo amongst 60898 breakers in the newer boards

Now the early series of breakers (bakalite in apperance) had the type dependant on the colour of the handle,

white = type 1 (I have only seen one of these)
green = type 2 (see a few of these)
orange = type 3 (see a few of these, again)
black = type 4 (often see whole boards full of these)

Now going by this, I assume the rcbo you have is type 4 (but I'm not 100% sure on this, but it seems a fair and failsafe assumption)

I have the data sheet somewhere, but from memory zs for a 30A federal type 4 na 3871 device is approx 0.66 ohm

 

[fattony]

Thanks Adam, data sheet emailed over, 30A = 0.64 Max Zs

 

[Adam_151]

Thanks Adam, data sheet emailed over, 30A = 0.64 Max Zs

And that will be on thermal trip, so it will take 0.4 sec to clear rather than sub 0.1sec, so watch your adiabatic/thermal withstand calcs

If those devices have mags, (not 100% sure) they would likely requires a zs of about half that quoted to operate (guesswork from drawing parallels with dorman smith load master devices)

Its up to you to decide how much you want to argue that the RCD part helps you with... (worms... everywhere )

 

[securespark]

I am half asleep..if you read what I wrote, ignore it, pat me on the head and say,

"Go back to sleep, Simon."