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)

 

[meggerlover]

then you need to brush up on your calculations. hint 6mm clipped direct will just dso it.

Thanks tele I have obviously missed something out , could you recap how you got to 6mm

 

[Kris]

Megga im still curious is this a domestic or commercial boiler , would think domestic at that size ?? thats why i asked about the 16mm seems huge

 

[snowhead]

Thanks tele I have obviously missed something out , could you recap how you got to 6mm

IET Forums - kw to amps, 3 phase calc

 

[telectrix]

30,000/ ( 1.732 x 400 ) = 43.3A. or a quick jobby. 30,000/3 = 10,000Watss /phase. 10,000/230 = 43.5A.

 

[meggerlover]

Megga im still curious is this a domestic or commercial boiler , would think domestic at that size ?? thats why i asked about the 16mm seems huge

Its an industrial boiler not used for heating it's used for boiler vast amounts if water in order to manufacture chemicals

 

[meggerlover]

30,000/ ( 1.732 x 400 ) = 43.3A. or a quick jobby. 30,000/3 = 10,000Watss /phase. 10,000/230 = 43.5A.

Whats your 1.732 represent

 

[telectrix]

root3. come on mate. this is basic stuff.

 

[D Skelton]

Electrician qualified to the current 17th edition requirements

What qualification exactly?

 

[meggerlover]

root3. come on mate. this is basic stuff.

My god I don't know where my head is

all lol I had to do is divide my 75 by sq root 3 to get 43amps

cheers guys

 

[meggerlover]

What qualification exactly?

A full bloody apprenticeship fully qualified ELECTRICIAN svq III
17 the edition 2394&5

 

[BES]

What qualification exactly?

A full bloody apprenticeship fully qualified ELECTRICIAN svq III
17 the edition 2394&5

Ah scottish

 

[D Skelton]

A full bloody apprenticeship fully qualified ELECTRICIAN svq III
17 the edition 2394&5

Still doesn't answer the question.

What number? 2330? 2357? 2397?

 

[meggerlover]

Yes no

 

[Andy78]

Megga im still curious is this a domestic or commercial boiler , would think domestic at that size ?? thats why i asked about the 16mm seems huge

As a gas fitter you are probably thinking of the boiler's size in terms of heat output, expressed in either kW or btu. A 30kW output boiler would be common in a domestic house. The calculation being done here is for the electrical energy (input) being drawn by the heater, in this case 30kW. In comparison a household kettle would draw about 2.2kW.

Your previous question about cable size ...... cable is measured by the cross sectional area of the conductors. 16mm is actually 16mm squared. It doesn't relate to the diameter of the cable as a whole.

 

[Badged01]

..... svq III ....

That explains why there is no root 3 then! ...... and fortunately no PF's or Eff's :smiley2:

 

[BES]

Yes no

So you were one of the ones who put both down on ballot paper.

 

[Kris]

root3. come on mate. this is basic stuff.

You guys should be gettin paid to teach on here lol, i find loads of guys claiming to be sparks on here but need to ask you guys for all the info,
Next door in plumbing forum unless they prove they are gassafe reged then we simply cant help them lol

 

[Kris]

As a gas fitter you are probably thinking of the boiler's size in terms of heat output, expressed in either kW or btu. A 30kW output boiler would be common in a domestic house. The calculation being done here is for the electrical energy (input) being drawn by the heater, in this case 30kW. In comparison a household kettle would draw about 2.2kW.

Your previous question about cable size ...... cable is measured by the cross sectional area of the conductors. 16mm is actually 16mm squared. It doesn't relate to the diameter of the cable as a whole.

Cheers andy

 

[Andy78]

You guys should be gettin paid to teach on here lol, i find loads of guys claiming to be sparks on here but need to ask you guys for all the info,
Next door in plumbing forum unless they prove they are gassafe reged then we simply cant help them lol

Unfortunately we have no such similar scheme. The only schemes we have drag people off the streets, take their money, tell them they are electricians, and devalue our trade. All with the full backing of the govt.

 

[Badged01]

Daddy, when I grow up I want to get into organised crime! ........ is that with the Govt or private sector son?

 

[D Skelton]

You still haven't answered my question meggerlover

 

[meggerlover]

You still haven't answered my question meggerlover

What is your question

 

[D Skelton]

What is your question

See post number #32

 

[meggerlover]

Still doesn't answer the question.

What number? 2330? 2357? 2397?

what at the hell are you talking about mate it's as svq level 3 apprenticeship

 

[Besoeker]

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

I think the "NO" vote has confused you.

Heard of:
Power = sqrt(3)V[SUB]L[/SUB]I[SUB]L[/SUB]cos(phi)
Rearrange to get I[SUB]L[/SUB]


See, it's not that hard, is it?

 

[D Skelton]

what at the hell are you talking about mate it's as svq level 3 apprenticeship

The City & Guilds 2397 is an NVQ level 3 apprenticeship. The thing is, it only takes five weeks.

It's all well and good saying you have got an apprenticeship, but what is it actually made up of. What certificates have you got and what actual qualification did you complete. I'm not talking in an alien language fella, this is a very basic question!

You have already expressed that you hold the City & Guilds 2394 and 2395 supplementary qualifications, I want to know what ACTUAL core qualification do you hold?

 

[meggerlover]

The City & Guilds 2397 is an NVQ level 3 apprenticeship. The thing is, it only takes five weeks.

It's all well and good saying you have got an apprenticeship, but what is it actually made up of. What certificates have you got and what actual qualification did you complete. I'm not talking in an alien language fella, this is a very basic question!

You have already expressed that you hold the City & Guilds 2394 and 2395 supplementary qualifications, I want to know what ACTUAL core qualification do you hold?

i don't know the c&g number of it it's not on my sjib gold card all I know is that it was a 4 year apprenticeship and u received a svq level 3
It's

 

[D Skelton]

i don't know the c&g number of it it's not on my sjib gold card all I know is that it was a 4 year apprenticeship and u received a svq level 3
It's

Thank you.

I still don't understand how you don't know what qualification you hold? Either way, I'd be annoyed if I were you as it is clear to me that whichever college you went to did not do their job properly in terms of providing you with a basic education!

 

[meggerlover]

Thank you.

I still don't understand how you don't know what qualification you hold? Either way, I'd be annoyed if I were you as it is clear to me that whichever college you went to did not do their job properly in terms of providing you with a basic education!

I know exactly what qualifications I have svq level 3 you total donut

 

[Pete999]

That explains why there is no root 3 then! ...... and fortunately no PF's or Eff's :smiley2:

Ive just got back from a rather large roast beef lunch at the Toby carvery, where several schooners of the red variety were consumed by yours truly PFs is that power factor? and Effs + efficiency? sorry for asking but the brain is not functioning as it should do.
Regards
A rather inebriated Pete999