30kw boiler cable calculations

[meggerlover]

Hi guys just a quick check in my calculations for a quote I'm doing

15meters clipped direct

30,000w divided by 400v
= 75a per phase

im using sy cable and think 16mm 5 core is best

What you guys think

 

[Pete999]

What about using square root of three in your calcs somewhere

 

[meggerlover]

This wouldn't change the current rating across the phases ??

 

[D Skelton]

This wouldn't change the current rating across the phases ??

Err, yeah, it would, quite dramatically too.

Why the SY? You haven't gone and mistaken it as being a 'tough' flex have you?

Out if interest, what quals do you have meggerlover?

 

[trev]

What about using square root of three in your calcs somewhere

Gasp! Who'd have thunked of using that?

This wouldn't change the current rating across the phases ??

Gasp! Obviously not you.

 

[micknew]

DIY section beckons.

 

[telectrix]

the mind boggles.

 

[trev]

Just about every bit of kit I've ever fitted like this has had a plate on it which gives information about what it should be connected to. These can be interpreted as manufacturer's instructions and should (most likely) be taken into consideration.
Does this boiler have one?

 

[D Skelton]

Just about every bit of kit I've ever fitted like this has had a plate on it which gives information about what it should be connected to. These can be interpreted as manufacturer's instructions and should (most likely) be taken into consideration.
Does this boiler have one?

Pah, who needs an info plate when you're as knowledgeable as the OP?!

That SY is bugging me more than the blunder of thinking that just splitting the power rating by three gives you phase current!

There's a smorgasbord of cable choices and containment options available to the OP, 99% of them more suitable than SY!?

 

[Kris]

Hi guys just a quick check in my calculations for a quote I'm doing

15meters clipped direct

30,000w divided by 400v
= 75a per phase

im using sy cable and think 16mm 5 core is best

What you guys think

Its probably a combi with built in timer lol

 

[Kris]

Whats the 16mm mean is that overall size of whole cable instead of 1.5mm core sizes ?? im no spark just a gas monkey guys

 

[meggerlover]

Swa not require it's in a industrial space , the plate on the boiler only says 30kw it's really old

fully qualified 17th ed
2394&5
QS

 

[meggerlover]

Whats the 16mm mean is that overall size of whole cable instead of 1.5mm core sizes ?? im no spark just a gas monkey guys

16mm 5 core cable

 

[Pete999]

This wouldn't change the current rating across the phases ??

Why is that then???

 

[Pete999]

Err, yeah, it would, quite dramatically too.

Why the SY? You haven't gone and mistaken it as being a 'tough' flex have you?

Out if interest, what quals do you have meggerlover?

All of them according to his profile

 

[D Skelton]

All of them according to his profile

Bovine excrement!

 

[D Skelton]

Swa not require it's in a industrial space , the plate on the boiler only says 30kw it's really old

Still doesn't mean that SY should be your next port of call!

fully qualified 17th ed
2394&5
QS

By 'fully qualified 17th edition' what do you mean?

 

[Pete999]

Bovine excrement!

That's the same as BS aint it?

 

[meggerlover]

Electrician qualified to the current 17th edition requirements

 

[telectrix]

then you need to brush up on your calculations. (hint 6mm clipped direct will just do it, but consider OCPD rating)