rcbo type c good or bad for domestic

[sdon26]

is installing rcbos type c bad or good

type b breaking capacity 30amp

type c breaking capacity 60 amps

i would say not to use type c due to cable failing before breaker

your views please!

is it ok to fit type c or not

 

[Mr Sworld]

is installing rcbos type c bad or good type b breaking capacity 30amp

type c breaking capacity 60 amps

i would say not to use type c due to cable failing before breaker

your views please!

is it ok to fit type c or not

The type b or c isn't to do with 'breaking capacity'. You can get a 32A rcbo in type b or type c. The type b,c (or d) is to do with inrush currents.

 

[Mr Sworld]

Welcome to the forum by the way!

 

[binky]

Not normal in domestic - but checkout Zs values for corresponding B & C RCBOs or RCDs

 

[paulh]

Type b,c,or d are all acceptable items to be fitted as overcurrent devices period. Perhaps you should elaborate on the circuit you wish to fit these too. After all if you are designing a circuit you will be in possession of all the relevant information.

 

[sdon26]

is it ok to fitt a 6 amp rcbo type c if zs under 3.06

 

[a1]

Welcome to the forum.

May I ask if you are a Spark?

 

[sdon26]

is it ok to fitt type c rcbo 6amp for lighting

if zs is below 3.06 ohms

problem is that wholesaler only has 6amp rcbos wylex

 

[paulh]

pass............please see my last post

.....

 

[Mr Sworld]

is it ok to fitt type c rcbo 6amp for lighting if zs is below 3.06 ohms

problem is that wholesaler only has 6amp rcbos wylex

The maximum Zs a 6A RCBO can have is 3.09 ohms. However that is at an ambient temperature of 10 degrees centigrade. However if the ambient temperature of that cable exceeds 10 degrees then the Zs will become too high for that RCBO (too high for a type B RCBO as well!).

That Zs seems to be very high for a lighting circuit. What type of supply do you have?

 

[SPECIAL LOCATION]

is it ok to fitt type c rcbo 6amp for lighting if zs is below 3.06 ohms

problem is that wholesaler only has 6amp rcbos wylex

I presume you are calcing your 3.06 as the 80% of the value from table 41.3 pg 49 Big Red book???

i.e. 3.83 x 0.8 = 3.064.

as Mr S says the O.S.Guide table 2D pg 103 lists max Zs as 3.09

So the actual answer to your question is Yes TypeC 6A RCBO is ok... Also assuming any other relevant correction factors have been applied to your Max ZS.

as a rough quick calc... lets say max Zs 3.00.

TN-S & Ze = 0.8 Max R1+R2 3.00 - 0.8 = 2.2

2.2 with 1.0mm T&E is 60.7m

2.2 with 1.5mm T&E is 72.8m

TN-C-S & Ze = 0.35 Max R1+R2 3.00 - 0.35 = 2.65

2.65 with 1.0mm T&E is 73.2m

2.65 with 1.5mm T&E is 87.7m

Again as Mr S said.... those Zs values would be a quite long lighting circuit for a domestic environment??????

whichever earth type and/or cable size used ALL 60m+!!! ; )

 

[jl-heating]

not much margin for error there, i would be inclined to investigate the circuit, as above, with in tolerance but only just.

can you give us more info on the circuit and earthing arrangements etc..