dangers on type c for domestic help

[scott g]

im doing inspection on flats and ive came across
all 61900 type c rcbo ive recommended changing to type b
due to type c for inductive loads . could cause overload
what is the general opinon on type c on domestic?

 

[DYCHE4230]

Hi

Am I reading this correctly?

Page 44 OSG table 7.1.

On a ring circuit for a TNS system, No RCD, 2.5/1.5 T+E
A "type C rcbo" is not permitted ZS being the prohibitive factor?

Thanks

 

[kung]

Thats what i read on 32A ring not permitted by ZS but ok on 6A lighting same for RCD & NON-RCD

 

[Spudnik]

Not really sure why a 32A RFC would ever need a c type to be honest.

 

[DYCHE4230]

Its not a case of needing one its a case that some manufacturers dont do b types so it would be useful if a c type was permitted.......

for instance I am doing a kitchen and the location of the CU makes it desirable to put in a RFC just for the kitchen..the previous electrician decided to put in a 16th split board and put the only ring and both lighting circuits on the rcd side. (niceic registered and told the customer he had done it to 17th regs????) so all lights and power on same rcd....I thought one solution would be to put kitchen ring on uprotected side on rcbo, but board is wylex and the b types rcbo's are hard to get hold of
and as discussed it appears that c types are not permitted for this type of circuit

 

[Spudnik]

You will also notice that it does not permit C type MCB's either although this is mainly for TNS systems.

Im trying to find info in the BRB with regards to this.

It just doesnt seem right to me.



Well looking in the BRB it gives EFLI values for type C MCB's and RCBO's so im not really sure what the OSG is on about.

 

[DYCHE4230]

Your right Jason it does give ELI figures, although they are low, but still if your readings are less then I don't see the problem either?? maybe someone can thro some light on this as the OSG says that the prohibitive factor is the Zs???????

 

[NickJPalmer]

Hi,
Just bought 3x Wylex type B RCBO's online from Gil-Lec. Previously I contacted Wylex (via Electrium online) to find out if they still manufacture type B's and they replied that they do.

Hope this is helpful.

 

[Spudnik]

Hi,
Just bought 3x Wylex type B RCBO's online from Gil-Lec. Previously I contacted Wylex (via Electrium online) to find out if they still manufacture type B's and they replied that they do.

Hope this is helpful.

Hager also still make b types. Just fitted a few.

 

[Plan]

One good thing about type c rcbo or mcb in a domestic lighting circuit because of it's higher tolerance doesn't always trip when a lamp blows.
As for the zs cos it's a rcbo the maximum allowed shoots up to 1666 ohms and if your measurements are that high debating between type b and c would be the last thing on my mind!

 

[scotsparky]

AS its an rcbo and therefore an RCD with overcurrent as long as it complys with Ib<In<Iz for the overload and the RCD complys with ZsIdn<50v then shurely its ok?