Air Con Unit - Rotary Isolator vs Fused Spur

[Damian30]

Hi,

Bit of a random question out of interest more than anything.

Fitting an domestic air con unit which requires 10 amp protection. Agreed with my electrician that we would just go with a Masterseal Plus fused spur rather that the usual rotary isolator you usually see with these units.

The manufacturer doesn't have a view on wheth this is the right approach but previously checking on this forum, it seems okay.

I am interested to know though what is the benefit of a rotary isolator over a simple fused spur. Or is it just that the rotary isolator are really for the industrial market.

Many thanks,

Damian

 

[Adam_151]

Rotary isolators are just convention for a few reasons.

When AC units started becoming popular in the 90's, a)IP rated accessories certainly were not a prolific as they are today, sockets were available but they were generally rubbish switches were available, but not sure sure about spurs.

Anyway at such times aircon units were often three phase, and if they were single phase often had a current demand greater than 13A. Remember that generally AC units were of the larger type and fitted to conference rooms, large open plan offices etc. It is only recently that every 10x10' office gets its own AC.

So the rotary isolator became a de-facto standard.

For a 10A SP inverter driven AC you could use an IP rated spur if you really wanted to, Its not what I'd generally do though

 

[DaftPunk]

I'd prefer to just have an isolator at the AC unit and keep the OCPD at the consumer unit.

 

[flyingsparks]

A rotary isolator can also be locked off so maintenance can be carried out safely.

 

[ericmark]

A fused spur can be locked off you draw the fused and put lock through the holder they are designed for that. However you are not locking off the neutral only the line. Although the switch does isolate neutral that is not locked. However with a lock through the fuse holder would seem a little pointless to turn on the switch.