Discuss 16kw 3 phase load. do I NEED 4 OR 6 SQ CABLE? Thank you in the Electrical Forum area at ElectriciansForums.net

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Plonker 3

What was the outcome of the cable calculations you did?
 

telectrix

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as usual we have all the info needed to make an accurate guess as to what size of string is required. if it's a motor,you could tie it down with a few yards of 1.5mm, doubled and twisted.
 

Guitarist

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Tell us what you think, along with your calcs, and we will check it over and see if we concur.
Can't say fairer than that...
 

plugsandsparks

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Stuff you need to know before running cables:
Zdb, breaker size and type, cable length. The 16KW is only a small component of the overall calculation which gives a hint at the breaker size but not type.
cheers
 
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kerryblue

The cable run is 20 mtr. Feeding 3 0.5w motors and 12 kw heating element. many thanks
 

darkwood

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Hi Kerry as others have said, we are not a free design service here, we are happy to help in areas where we see you just need a little help to get you over a problem in their calcs but you are posting this and other threads and showing no info' that we would require or the fact that you dont seem to have tried any working out whatsoever. This would suggest that you are not an electrician and designing such an install would require one. Please correct us if we are wrong and offer all the relevent info needed to work out cable sizing and as other thread asks the '2.5no's singles in a conduit' could you show us your calcs so we can point your errors or confirm it to be correct.
 

telectrix

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so use the OSG and calculate current and volt drop for , say, 2.5mm cable and see if it's big enough. if not, then go to 4mm. etc.
 

malcolmsanford

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The cable run is 20 mtr. Feeding 3 0.5w motors and 12 kw heating element. many thanks
KB my first post was a little tongue in cheek but this one is a little more to the point.

Are you sure you are talking about 0.5w motors or could that be 0.5kw which are 500 watt motors

You now have separate values on your design with concern of volt drop. The motors can take a higher than the 5% VD allowed for the heating elements

You are now talking about inductive and resistive loads, which to be honest is not that critical in this situation but you now need to divide this load up into different circuits.

So are you now going to feed a distribution board and then run your motor and elements from this local board, or are you going to take 2 circuits from an existing board

Honestly the list can go on, these above are just me thinking about this for less than a minute. There are so many variables to this that you need to tell us a lot more
 

Guitarist

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There are so many variables to this that you need to tell us a lot more
The other option is to pass this work on to an electrician with experience in this field.
There is no shame in admitting that another firm may be better suited to a particular job, and while I keep hearing "I need the money, so I can't turn down the work", we all need to be fair to our customers.
There seem to be more and more people out there "having a go", without the knowledge or experience to carry out the work safely.
 

plugsandsparks

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The cable run is 20 mtr. Feeding 3 0.5w motors and 12 kw heating element. many thanks
Zdb? - also now you have 4 devices, is this cable going to a control panel ?
Assume 0.5W is a typo for 0.5KW, the reason for needing the Zdb is sometimes with D type breakers ELI comes into play before volt drop and current carrying capacity.
It has caught out numerous sparkies (including myself) from what i find in testing.
 
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