Is this acceptable?

[TheApprentice]

So the incoming power is coming from X1 and three phase is being distributed to Q1 using 25mm cable. Phase 1 & Neutral are going to Q2. I was curious as to what cable size is acceptable going to Q2? I assumed it would also need to be 25mm but I've been told as its pulling a maximum of 1A that 1mm is acceptable.
Is this correct or is this a safety hazard?
Thanks in advance, first time post and new to the industry.

 

[Bobster]

Perfectly acceptable, so long as the wiring is in an area not likely to be subject to damage, and the OCPD (-Q2) is less than 3 meters away.

 

[Deleted account]

The pfcc and pscc on a circuit run in 1 mm is going to be a lot lower than is required to break the incoming.
So no 1 mm won’t do it.

Edit : having read robs post. If there is a very low chance of a fault occurring then yes I may agree with him, but it’s not something I’d do.

 

[TheApprentice]

Fantastic, thanks for your help Rob

 

[snowhead]

Edit : having read robs post. If there is a very low chance of a fault occurring then yes I may agree with him, but it’s not something I’d do.

It's within a control panel, it's very common to see this and also panel lights, maintenance sockets and BMS supplies fed off the incoming side of the panel isolator. All marked, live when panel isolator is off.

 

[Bobster]

The pfcc and pscc on a circuit run in 1 mm is going to be a lot lower than is required to break the incoming.
So no 1 mm won’t do it.

Edit : having read robs post. If there is a very low chance of a fault occurring then yes I may agree with him, but it’s not something I’d do.

It's a common method of doing things in control wiring.

However the stipulation is the wire length (<3m) and it hasn't to be likely damaged, so realistically, inside trunking within a control panel it's not.

 

[davesparks]

I agree 1mm will be fine, however I would personally read that drawing as indicating it should be 25mm.

 

[Megawatt]

View attachment 51295
So the incoming power is coming from X1 and three phase is being distributed to Q1 using 25mm cable. Phase 1 & Neutral are going to Q2. I was curious as to what cable size is acceptable going to Q2? I assumed it would also need to be 25mm but I've been told as its pulling a maximum of 1A that 1mm is acceptable.
Is this correct or is this a safety hazard?
Thanks in advance, first time post and new to the industry.

View attachment 51295
So the incoming power is coming from X1 and three phase is being distributed to Q1 using 25mm cable. Phase 1 & Neutral are going to Q2. I was curious as to what cable size is acceptable going to Q2? I assumed it would also need to be 25mm but I've been told as its pulling a maximum of 1A that 1mm is acceptable.
Is this correct or is this a safety hazard?
Thanks in advance, first time post and new to the industry.

The apprentice from what I’m seeing is the arrow you drew was pointing at the grounding conductor and after 30 amps you can defrayed the equipment ground. Looks fine to me

 

[Megawatt]

The apprentice from what I’m seeing is the arrow you drew was pointing at the grounding conductor and after 30 amps you can defrayed the equipment ground. Looks fine to me

Derate not defrayed is what I meant to type

 

[James]

Although it is fine to do that as discussed above.
I prefer to size cable in that scenario bigger than required.
I think I would have used 4mm, apart from any other reason, it tends to fit the larger terminals found in the isolator a bit better.

 

[Megawatt]

Although it is fine to do that as discussed above.
I prefer to size cable in that scenario bigger than required.
I think I would have used 4mm, apart from any other reason, it tends to fit the larger terminals found in the isolator a bit better.

It’s never a bad idea to oversize

 

[Deleted account]

It’s never a bad idea to oversize

Up to a point. But in this scenario definitely.

 

[James]

It’s never a bad idea to oversize

Is that why my wife has a special smile when the postman is around?

 

[Intoelectrics]

Is that why my wife has a special smile when the postman is around?

My missus always says "sometimes good things come in small packages" I think she's just trying to make me feel better.

 

[TheApprentice]

Thanks for all the inputs guys, much appreciated!