What cable size and breaker would I need for two extractor fans in a public toilet? 1.5mm 3 core and a 20amp rcbo?

[PaulDun41]

What size cable for 2 extractor fans in a public toilet?

 

[buzzlightyear]

are you a spark?

 

[PaulDun41]

are you a spark?

Yes, just asking the question

 

[James]

Total circuit load in amps?

 

[westward10]

Your opening question is somewhat bizarre if you are a qualified electrician.

 

[MJPD29]

Yes, just asking the question

It seems rather basic

 

[Soi disant]

What size cable for 2 extractor fans in a public toilet?

One with a current carrying capacity greater than or equal to the rating of the breaker, with low enough impedance to ensure disconnection times are met and voltage drop is not too high, and greater than or equal to the load, which in turn should be less than or equal to the rating of the breaker.

Of a type suitable for the conditions where installed.

 

[James]

One with a current carrying capacity greater than or equal to the rating of the breaker, with low enough impedance to ensure disconnection times are met and voltage drop is not too high, and greater than or equal to the load, which in turn should be less than or equal to the rating of the breaker.

Of a type suitable for the conditions where installed.

Technically correct but somewhat unhelpful

 

[timhoward]

What size cable for 2 extractor fans in a public toilet?

Be careful mate. This is a public environment where literally anyone can come into contact with this work, and your neck is on the line as the bloke that installed it.
In the nicest way possible, if you need to ask this you shouldn't put yourself in the firing line.

 

[PaulDun41]

Be careful mate. This is a public environment where literally anyone can come into contact with this work, and your neck is on the line as the bloke that installed it.
In the nicest way possible, if you need to ask this you shouldn't put yourself in the firing line.

Thanks mate, I was just asking as someone’s done it and debating if they had installed the correct cable?

 

[timhoward]

Thanks mate, I was just asking as someone’s done it and debating if they had installed the correct cable?

That wasn't very clear from the question!
So you are saying it's currently 20 amp RCBO with 1.5mm 3 core.
Are there any fused isolators for the fans or are they connected directly?

 

[Mike Johnson]

Total circuit load in amps?

Most domestic fan manufacturers require a 3amp inline fuse for their extractors and its normal to have a three pole isolation switch, one assumes this is in a work environment, therefore industrial/commercial?

 

[timhoward]

At the moment my only answer is that no installation method of 3 core flat PVC 1.5mm cable is rated for 20 amps. I was wondering if there were FCU's by the fans and that overload protection was provided that way.
It's likely the RCBO is oversized but can't be sure without knowing more about the fans who knows.
If the OP has a clamp meter it would be interesting to know the current draw with both fans on.

 

[Soi disant]

At the moment my only answer is that no installation method of 3 core flat PVC 1.5mm cable is rated for 20 amps.

Method C.

 

[LastManOnline]

Method C.

Strictly speaking method C is 19.5 amps. But we won't haggle over 0.5 of an amp. In fact running a 1.5mm directly to the 2 fans is also perfectly safe on a 20amp rcbo. But is it conventional, good practice or advisable? No