3 core cables in industrial application

[m sleem]

We have a project (expansion of ceramic factory), the client requests us to provide 3.5 core cable"reduced neutral" from transformer to panel & 3 core cable "without neutral" from panel to equipment's control panel, the client says "the control panel includes a transformer to step down the voltage level to the required level by the control circuits". We advised the client to continue using the 3.5 core cables every where because the order of the 3 core cables will be manufactured as a special order which might be more expensive than the order of the 3.5 core cable, aside from that we can utilize the unused neutral as a grounding conductor.
My question here, does the step down tr clear the harmonics of the control circuits? if no, so the neutral wire is necessary up to the control circuits. Please share your idea to find out the best solution.

 

[lakee911]

Transformers can't necessarily clear the harmonics, but they may be able to attenuate them to a point where it's no longer an issue.

 

[petersonra]

what is a 3.5 core cable? does the ".5" indicate a reduced size N?

here in the US you would need a grounding conductor in each cable so it would do you no good to try and use the N conductor as a grounding conductor.

 

[GoldDigger]

what is a 3.5 core cable? does the ".5" indicate a reduced size N?

here in the US you would need a grounding conductor in each cable so it would do you no good to try and use the N conductor as a grounding conductor.

Also, the the conditions that justify a reduced neutral will not necessarily justify a reduced EGC.

 

[m sleem]

what is a 3.5 core cable? does the ".5" indicate a reduced size N?

here in the US you would need a grounding conductor in each cable so it would do you no good to try and use the N conductor as a grounding conductor.

3.5 means 3conductors + half conductor for neutral, this was commonly used in the past but now & Due to the non-Linear loads we have to have full conductor size for neutral. If the neutral is not required for the equipment panel, so the .5 neutral shall be used as the grounding conductor.

 

[m sleem]

Also, the the conditions that justify a reduced neutral will not necessarily justify a reduced EGC.

But, the EGC would never reach .5 of the phase conductor.

 

[iwire]

Am I correct that the basic question here is do you have to provide a neutral even if it is not going to be used?

The answer is generally no.

 

[Smart $]

Am I correct that the basic question here is do you have to provide a neutral even if it is not going to be used?

The answer is generally no.

And without a neutral, there is no need for concern about additive triplen harmonics.

 

[m sleem]

Am I correct that the basic question here is do you have to provide a neutral even if it is not going to be used?

The answer is generally no.

What is your opinion about using the unused neutral for grounding?

 

[petersonra]

What is your opinion about using the unused neutral for grounding?

I don't have an issue with it if it is sized appropriately. I don't use cables much and I don't recall off hand what the rules are on re-identifying individual conductors in a cable.

This seems like a non-US application so what you can or should do there might not apply in a NEC application. A cable here would have to have the grounding conductor built in.

 

[lakee911]

I don't have an issue with it if it is sized appropriately. I don't use cables much and I don't recall off hand what the rules are on re-identifying individual conductors in a cable.

This seems like a non-US application so what you can or should do there might not apply in a NEC application. A cable here would have to have the grounding conductor built in.

From what I recall, you're able to re-id any color and size of a wire in a cable for the use as a ground. All cables here in the U.S. don't necessarily have a grounding conductor built in.

 

[iwire]

What is your opinion about using the unused neutral for grounding?

If it is white I could not do that.

 

[m sleem]

If it is white I could not do that.

Normally, it's black & phases are (red, yellow, blue).

 

[petersonra]

Normally, it's black & phases are (red, yellow, blue).

might not be compliant with US standards.