40A RCBO but Neutral Lead Rated 32A

[aesmith]

Hi,

Not sure if I'm missing something, but surely the Neutral lead on an RCBO will carry the full load return current. I just noticed that on a 40A RCBO the Neutral lead is only rated 32A, or is marked as such. What do you think?

Untitled

• aesmith
• 15 Dec 2013
• 1

 

[ricicle]

The fly lead is tri-rated and as such will carry 40A

 

[EFLImpudence]

Then why does it say 'max 32A'?

I have just looked at a 20A RCBO and it is the same - which is obviously alright.

 

[aesmith]

I've just emailed Hager technical, I don't know whether they respond to such questions but might as well give it a go.

 

[Ahtyrrell]

interesting point, I'm sure it wont be an issue for a foot or so of cable

 

[aesmith]

interesting point, I'm sure it wont be an issue for a foot or so of cable

Possibly. I'm not specially happy about installing something that by design will exceed the manufacturer's marked ratings.

 

[Adam_151]

The fly lead is tri-rated and as such will carry 40A

But at what temperature will it run at to do so?

 

[ricicle]

Has anyone ever come across a melted one (through overload not loose connection) ?
That will give you your answer!

 

[EFLImpudence]

Then why does it say 'max 32A'?

 

[aesmith]

Has anyone ever come across a melted one (through overload not loose connection) ?
That will give you your answer!

Not sure it will. At the moment I don't know if I've just got a duff one fitted with the wrong N fly lead. Mine might be the only one like this. I'm not sure fitting it and waiting to see if it melts is the correct course of action.

Hopefully someone will be able to look at one or more ADN140s of their own, to see whether they're all marked like this, and if that's the case you may possibly be correct.

 

[AndyPRK]

I though all rcbos had the same thickness cable

 

[RF Lighting]

Just measured a 32A rated hager flylead, and it seems to be a 5.0mm² conductor, which will be fine for 40A

 

[EFLImpudence]

Then why does it say 'max 32A'?

 

[RF Lighting]

Dunno, I don't make them.

 

[EFLImpudence]

Unless I am to lose all confidence in my favourite manufacturer, I want to know.