32amp radial

dokkan1080 · Feb 9, 2020

In a school today helping an approved contractor.

There is a over door fan heater on a 32amp radial fed off a rotary isolator.

It then goes into a bank of 3 switches that are used to control it.

The swtchs are double pole rated at 20 amps.

Isn't that a danger being on a 32 amp 4mm mcb

buzzlightyear · Feb 9, 2020

No , not over rated 4mm on a 32 amp
Plus the rating of the heater .

static zap · Feb 10, 2020

dokkan1080 said:
bank of 3 switches that are used to control it.

are these On/off FAN and power settings ?
(may share the current)

dokkan1080 · Feb 10, 2020

static zap said:
are these On/off FAN and power settings ?
(may share the current)

Yes ones to turn it off and on, the other two are power settings

Wilko · Feb 10, 2020

Hi - what is the kW rating of the heater?

Julie. · Feb 10, 2020

If the heater is over 20A then the switch would be overloaded (even if elements are split) as one is used to switch to whole load.

As it's a fixed load, the cable and switches only need to be rated for the load - not the protective device, so it all depends on the size of the load.

davesparks · Feb 10, 2020

Are you sure it's a 20A switch in the drid and not a 32A?

dokkan1080 · Feb 10, 2020

davesparks said:
Are you sure it's a 20A switch in the drid and not a 32A?

Julie. said:
If the heater is over 20A then the switch would be overloaded (even if elements are split) as one is used to switch to whole load.

As it's a fixed load, the cable and switches only need to be rated for the load - not the protective device, so it all depends on the size of the load.

Didnt think you could get a 32amp grid switch...