FDB11 RCD Units Advice

[Hundleton1]

Ho guys anyone know much about these?

Got a burger van thats been out of use for some time. Been bought by a new owner and needs sorting out.

The incoming goes into a large FDB 40A 35ma RCD unit, this then feeds a steel 10 way Mcb board, from this the lighting, cooker and fridges go straight out, then single feeds go out to 3 x FBD11 20A 20ma RCD MCB units. Then the sockets split between the three of these in rings.

Not had chance to test anything just been over to have a quick look that ended up being a full system trace.

Its a hell of a lot of kit on the back wall, What are these like, considering ripping all out and sticking in a new board.

Far tidier I know that.

 

[Sintra]

For one I've never heard of either a 35mA or a 20mA RCD

 

[Hundleton1]

Surprised me as well, its whats on the labels

 

[Sintra]

Any pics of the unit?

 

[Hundleton1]

Here with the covers off

 

[Clive P]

Hi.

Just had a quick Google seems 20 and 35mA RCD's are available.

Regards.

 

[davethsparky]

How big's the burger van? 3 rings could do a 4 bed house comfortably!

What's the incoming on that thing? Normally we only get them turn up at events with a 16amp appliance inlet on them.

 

[Hundleton1]

Its fitted with a 63A blue plug,

Its a decent size van bit bigger than the normal ones but as you say 3 rings really ?

I worked out there can only be 2 or 3 sockets on each ring.

Its one hell of a setup for the size of the van.

 

[davethsparky]

Wow, can't say I've ever had one of them turn up on a 63! Normally they are a 16 for lights and bits and pieces with all the cooking done on gas.
Where are they planning on using this? We always allow just a 16 per van when we do event power, 63 would be costly to supply and take a bit more thinking about to keep our generators balanced.

 

[Hundleton1]

Its surprised me a bit.

Its now going as a van on a bike repair shop, its going to be all electric,

Its having a new griddle and appliances as its been standing all locked up for 3 years.

Looking at installing at lest 60A feed as Have been working out what's going in

20A Griddle
6A Lighting and vent fan
2 x 32A rings as your going to have toasters, frier and kettle, posable Water boiler, fridges and freezer
16A water boiler for sink

Now everything is in theory will run at same time but its a house hold load at least

 

[itselectric]

I wired a socket for a burger van and put in a single phase 16a rcd socket after asking the polish chap who was going to be using it.

When it turned up it was 400v 3 phase 32 amp supply required. The van was no bigger than our run of the mill vans.
Needless to say I wasn't chuffed.
The van had been imported from Poland
It lasted about 2years then he packed up lock stock and barrel and went back home.

 

[davethsparky]

Why ring mains? Surely there is no sensible case for a ring over radial circuits in a burger van?

So is this van going to be permanently located?

 

[Hundleton1]

Yep permanent , I agree on the radial but cabling is all good so no need to tear out really, its all singles pulled in trunking and conduit.

Its all even label up in every socket and in each board.

Going to put in a 63A sub main with 10mm SWA and replaced the current 5 boards with a single RCD Board.

As I said cabling is good, the sockets being split in 3 rings is massively overrated however as its in place and tested fine they want it to stay

Limited budget on this one.

 

[davethsparky]

Fair enough, I though you'd said you were ripping out and starting over.

Had another look at the pictures and that RCD arrangement is interesting, seperate current sense and trip unit with shunt trip arrangement on what looks like a TP breaker being used as DP, you don't see arrangements like that in small scale stuff these days! I'm guessing that's from the early days of RCDs

 

[Hundleton1]

It caught me out at first look as I assumed it was TP,once I pulled the covers It was a bit of a what the hell moment, the Main RCD Unit is huge, will take some more pictures Monday.

I may split the rings Into radials on 16A mcb but still have not quite figured out where everything goes yet.

Once I tear the boards out and get all the patch cables from the boards out It will be easier

 

[Hundleton1]

Pictures of the main incomer RCD unit.

Its huge

 

[davethsparky]

Brilliant, would be useful as a means of showing people who don't understand exactly what is going on inside the magic little box with a test button on it.

 

[ahtyrrell]

Surely the earth wire shouldn't be fed through the sensor should it? otherwise any leakage to earth would come back on the wire and cancel out. Am I right in thinking that the device trips the TP MCB by effectively overloading the phase with the small brown wired going through? or is the module to the right the part that causes it to disconnect

 

[davethsparky]

Doesn't look like the earth is going through the sense coil to me, victim only viewing on my phone .

It's the same setup as a residual current/leakage relay and shunt trip used with MCCBs to give the same protection.
You have a device on the side of the normal breaker which is interlocked with the tripping mechanism of the breaker and trips it that way.