“Domestic” Cable for Motor Applications

[IAmSparkytus!]

Good afternoon all,

First time posting on here so not sure if this is the correct place to post this but I’m sure you will all correct me if it isn’t.

My query today is whether anyone can see a problem using twin and earth to supply motor units fed from C rated MCBs?

I have enquired with an NICEIC assessor who says he doesn’t see the problem with it but still remain unsure and uncertain within my head.

Maybe this is unacceptable in all circumstances, maybe it’s ok for shorter runs but not larger runs, could be that it’s perfectly fine.

Please let me know your thoughts! Thanks.

 

[suffolkspark]

Solid cores into a unit which is subject to vibration? And it will look rough as old bulls ears. Terminate the t/e locally and use an appropriate flex onto the motor

 

[westward10]

Provided it is suited by the installation method it should be fine. I would not use it for the final motor connection though.

 

[Strima]

All depends on the installation method and external influences.

Also how is the motor connected?

Is the cable and termination subject to vibration etc?

Need more info really.

 

[Squid]

When I used to wire motors up in the past it was a connection to a 4x4 box then either a copper or flex from the box to the motor as mentioned above its the vibrations as some motors sit on heavy duty rubber shock absorbers more info needed as then better advice can be given.

 

[Pete999]

Good afternoon all,

First time posting on here so not sure if this is the correct place to post this but I’m sure you will all correct me if it isn’t.

My query today is whether anyone can see a problem using twin and earth to supply motor units fed from C rated MCBs?

I have enquired with an NICEIC assessor who says he doesn’t see the problem with it but still remain unsure and uncertain within my head.

Maybe this is unacceptable in all circumstances, maybe it’s ok for shorter runs but not larger runs, could be that it’s perfectly fine.

Please let me know your thoughts! Thanks.

Will that be single phase motors or three phase motors, solid core condctorsare not ideal for machines that are subject to vibration

 

[IAmSparkytus!]

In this instance there are 10 motor units positioned throughout a service duct which runs around the perimeter of a building.

The cables are grouped and tie wrapped to a cable tray, go into individual rotary isolators, and then into the units.

Cable runs range from 10-90 metres from the distribution board.

 

[IAmSparkytus!]

Will that be single phase motors or three phase motors, solid core condctorsare not ideal for machines that are subject to vibration

Single phase.

 

[westward10]

What are you using for the final connection.

 

[suffolkspark]

Is this already installed or are you installing? Is this perimeter run internal or external to the building?

 

[Pete999]

Solid cores into a unit which is subject to vibration? And it will look rough as old bulls ears. Terminate the t/e locally and use an appropriate flex onto the motor

 

[IAmSparkytus!]

Is this already installed or are you installing? Is this perimeter run internal or external to the building?

This is an existing installation I have come across. The service corridor is internal with no chance of the weather affecting it.

Usual procedure for myself would be to install using SWA or NYY.

 

[Dillb]

Aside from the responses above saying about vibration on the motor terminals, why did you think it was not suitable to use? What exactly is "domestic" cable?

 

[Pete999]

Aside from the responses above saying about vibration on the motor terminals, why did you think it was not suitable to use? What exactly is "domestic" cable?

I'm sure the DI brigade will be able to help.

 

[westward10]

So why do you want to know if it is existing?

 

[AJshep]

So the T&E terminates into the rotary Isolators. What cable have they used from the rotary isolator ?
I'd be more interested In disconnection times, what size are the motors ? are the motors incorperated into a pre-wired unit or are they independantly switched on via the Rotary isolator ?
552.1.2

 

[IAmSparkytus!]

I would like to know out of curiosity, westward10 - is that unheard of? Might be useful information in the future you never know.

And i’m not sure, just didn’t seem like it was good practice for some reason in my head. Can’t put a finger on it.

 

[westward10]

Thought you might be doing an EICR. What are the final connections done with.

 

[AJshep]

Oh I just assumed the OP was doing an EICR

 

[Risteard]

Aside from the responses above saying about vibration on the motor terminals, why did you think it was not suitable to use? What exactly is "domestic" cable?

To be fair T&E type cable is domestic cable. It's really not designed for non-domestic use. Such use might be described as "value engineering".

 

[Dillb]

To be fair T&E type cable is domestic cable. It's really not designed for non-domestic use. Such use might be described as "value engineering".

Really? I have seen it used in many commercial and industrial installs.

 

[Risteard]

Really? I have seen it used in many commercial and industrial installs.

Value engineered ones.

 

[Dillb]

Value engineered ones.

No just ones where it is suitable for the enviroment installed in.

 

[Risteard]

No just ones where it is suitable for the enviroment installed in.

LOL. T&E cable standards specify it as a domestic cable. I will never accept that it has a place in non-domestic installation.

 

[Dillb]

LOL. T&E cable standards specify it as a domestic cable.

Wheres that then? Any BS standards mention it?