Odd fan wiring.

[GBDamo]

Had three extractor fans, 15yr old, all non functional which was odd to start with.

All three were supplied with a three core and earth from a fan isolator, all very normal but the fans were not timer fans, odd.

Was on the verge of going out to get new ones but checked the voltages at the fans and got 240V PL-N and 70V SL-N?

Had a look in the fan isolators and all three had the over run timer wired up in the fan isolator back box.

Has anyone come across this before?

Could someone with the technical genius explain why this might be done, bearing in mind there was a three core and earth pressent.

https://www.google.co.uk/url?sa=t&s...FjAAegQIBxAB&usg=AOvVaw1m2I6xBkFfFpHoUG2uyLFw

[/URL]

These were the timers being used.

What are the potential issues with these being remote from the fan as opposed to in the fan?

 

[ipf]

You'd still need a second live at the fan for run on, via the controller, so I would imagine there would be provision. Two signals, one for run, one for run on.

 

[GBDamo]

You'd still need a second live at the fan for run on, via the controller, so I would imagine there would be provision. Two signals, one for run, one for run on.

No, the fans only had a L and N terminal, with the over run function carried out by the unit at the fan isolator which commected to Sl, PL and N and out puttedd to the fan via a sinle live wire.

 

[ipf]

No, the fans only had a L and N terminal, with the over run function carried out by the unit at the fan isolator which commected to Sl, PL and N and out puttedd to the fan via a sinle live wire.

That's understandable. One line being controlled in either. But you said they were wired in 3 core. If so, how were they connected?

 

[GBDamo]

That's understandable. One line being controlled in either. But you said they were wired in 3 core. If so, how were they connected?

Which is odd, they were and the PL was live and taped over.

I don't see the need to do this here although it could be an option where a 3core is not available and a time fan is required.