Tri rated cable and grouping factor

Jako13! · May 28, 2022

Hi guys I’ve got a motor starter I’ve come across and looking at the electrical drawings it’s originally had 35mm tails from a 100amp fused isolator switch. This has been replaced with 25mm tri rated cable. Looking at the specs for BS 6231 I can see the conductor can take 136 amps. Motors are 37kw. Is there anything I’m missing. How do you apply grouping factors for a panel running a single motor or is grouping factors not applied?

Thanks guys

WallaceP · May 29, 2022

Treat it as any other trunking for grouping factor. Consider ambient temp on panel and how often the load will be starting and stopping

Jako13! · May 29, 2022

Am I right in saying the ambient temp is 40degrees for tri rated?

Jako13! · May 30, 2022

I just found this so 45degrees in free air.

Jako13! said:
Am I right in saying the ambient temp is 40degrees for tri rated?

Jako13! · May 30, 2022

WallaceP said:
Treat it as any other trunking for grouping factor. Consider ambient temp on panel and how often the load will be starting and stopping

If it’s 3 phase 3xsingle core and control circuits within the trunking how does this related to how many loaded circuits? Found this in bsen 60204-1