Query about eddy effects

[bhamoggy]

So Allianz insurance inspector has pulled up a C3 ( I know it’s not mandatory) about magnetic effects from a circuit.
so we have a small 9-way board with cables entering via galvanised trunking and thru 3 20mm couplers.
They’re all single phase circuits but he’s highlighted one circuit that has the line coming into the board thru one coupler and the neutral coming in thru a different coupler.
What’s your thoughts on that?

 

[loz2754]

I too would be inclined to C3 this. Unless the circuit current is very high, the effects of eddy currents are likely to be very small.

 

[telectrix]

probablyi nsignificant if the current is low. how easty is it tomove the N to the L entry??

 

[bhamoggy]

There’s not a lot of room with the other circuits which is why it may have been installed like that.
someone said before that it’s mainly 3-phase you have to worry about with eddy effects.

 

[Petej999]

So Allianz insurance inspector has pulled up a C3 ( I know it’s not mandatory) about magnetic effects from a circuit.
so we have a small 9-way board with cables entering via galvanised trunking and thru 3 20mm couplers.
They’re all single phase circuits but he’s highlighted one circuit that has the line coming into the board thru one coupler and the neutral coming in thru a different coupler.
What’s your thoughts on that?

C3 every time have you seen the results of Eddy current heating
'

 

[James]

probably easier to move the cable than to calculate out the heat gain from the eddy currents
and the acceptable heat loss through the enclosure.

 

[FarmersFriend]

How about replacing the bushes with grommets and cutting a slot between the two holes , the two entries become one with the phase and neutral in it
?

 

[Lucien Nunes]

Technically incorrect but with a small circuit passing through a thin steel enclosure, unlikely to cause any noticeable effect. IIRC John Ward made a demo video showing that even with 100A passing through two separate knockouts in a CU, or so the temperature rise was only a degree or two. It becomes a problem once you get up into the hundreds of amps, with heavy gland plates on transformers etc.