3 phase machines

[Hawk]

Was looking at a job where the customer wants another dishwasher same as the one that they have. The one they have has a rating plate which says 6.6kw/12.4A. It is wired in 6mm on a 40A mcb. Length of run is 10mtrs. Now I would have thought that 400x1.732=692.8
6600/692.8=9.53A therefore a 2.5mm cable on a 16A mcb should suffice. Am I missing something?

 

[Pete999]

Was looking at a job where the customer wants another dishwasher same as the one that they have. The one they have has a rating plate which says 6.6kw/12.4A. It is wired in 6mm on a 40A mcb. Length of run is 10mtrs. Now I would have thought that 400x1.732=692.8
6600/692.8=9.53A therefore a 2.5mm cable on a 16A mcb should suffice. Am I missing something?

Three Phase Current - Simple Calculation

 

[davesparks]

Was looking at a job where the customer wants another dishwasher same as the one that they have. The one they have has a rating plate which says 6.6kw/12.4A. It is wired in 6mm on a 40A mcb. Length of run is 10mtrs. Now I would have thought that 400x1.732=692.8
6600/692.8=9.53A therefore a 2.5mm cable on a 16A mcb should suffice. Am I missing something?

I don't know what you are trying to calculate there but if the data plate says 12.4A then that is your design current.
A 16A mcb seems appropriate.
I cannot comment on cable size as you have not provided enough information, but at a guess I'd assume 4mm until further information is provided.

 

[snowhead]

Do you know if the supply was put in for the current dishwasher?

It may be the original installation was for a larger more powerful dishwasher.
This may have been downgraded and now they've found out it's too small and need additional capacity.

 

[Hawk]

Snowhead I think you may have hit the nail in the head.

 

[snowhead]

Snowhead I think you may have hit the nail in the head.

Where do I send the invoice?

 

[davesparks]

Do you know if the supply was put in for the current dishwasher?

It may be the original installation was for a larger more powerful dishwasher.
This may have been downgraded and now they've found out it's too small and need additional capacity.

Good old cost saving that ultimately costs more!

 

[Hawk]

Hahaha I'll get George Agdgdgwngo to "wire you the monies"

 

[Hawk]

Future proof Dave!

 

[davesparks]

Future proof Dave!

What's future proof? Do you mean my estimate of 4mm? That's based on the fact that the generally default cable size for small power commercially these days is 4mm, this effectively automatically accounts for grouping, VD etc on standard small power circuits such as this.