Eddy Currents

[skillsassessor]

Hi,

A question I was asked the other day, does the line and neutral mains tails and main earth all have to go through the same hole in a single phase metallic consumer unit or can the neutral and main earth go through another knock out hole and use some form of nylon stuffing gland ? ( Assume IPx4 rating is maintained on accesible horizontal surfaces)

Thanks

 

[Robin Spark]

Afaik line and neutral must go through same hole on a metal enclosure otherwise eddy currents will be created.

If its not possible to do this i think you can cut a narrow slot between two knockouts to effectively make it one hole, however its not something i have needed to do

 

[Evans Electric]

A single core will creat eddy currents on it's own , add the neutral or another phase or as Robin says , put a sawcut between the holes. 

 

[Sidewinder]

Try 521.5.1

 

[skillsassessor]

Thanks for the replies, Line and neutral will go together through one hole, can the main earth then go through a separate hole without the need for a saw cut ? ( it will fit with the L&N but was asking for ease of installation and neatness )

Thanks

 

[Sidewinder]

The reg I have listed above will clarify this for you.

 

[Evans Electric]

As Sidey said , check the reg ...but I can't see what difference the earth makes TBH . 

I take it you are not actually a SkillsAssessor then ?  

 

[NozSpark]

As Sidey said , check the reg ...but I can't see what difference the earth makes TBH . 

I take it you are not actually a SkillsAssessor then ?  

Could you imagine if they were?

Class room full of students..... "hang on a minute whilst i check that out on the internet"...... LOL

 

[Robin Spark]

Thanks for the replies, Line and neutral will go together through one hole, can the main earth then go through a separate hole without the need for a saw cut ? ( it will fit with the L&N but was asking for ease of installation and neatness )

Yes the protective conductor can enter through a seperate hole. Read the bottom line!

Thanks

 

[binky]

one hole for the lot = no problems

 

[Tony S]

If you are worried by the slot between the individual holes, fill it with epoxy.

If you use plastic or brass glands, please don’t do the trick a contractor pulled on our plant. He was given the brass glands and locknuts. He used steel locknuts because no one would ever know inside the transformer LV box.

We did! It went with one hell of a bang!

 

[SLIPSHOD & SLAPDASH]

.

 

[Old Rifle nut]

Yes live and neutral must go the same conduit if using RMC or lighter electroplated metallic tubing,EMT in Australia,saw a guy who should have known better wire a factory sub board extension with 3 50mm DLO  cables per phase and neutral,all in separate conduits conduits them selves used for earthing,ok but I would have run a 75 mm earth as well,400ft run 60 volt drop lucky enough remained at each end so this could be corrected easily,130 c cables meant they were ok too.

 

[SLIPSHOD & SLAPDASH]

Welcome old rifle nut. This is an old thread i accidentally posted on when linking it to a very recent one. This is a UK forum & i dont think we have any one from Oz here so it will be interesting to see some differences in the work