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Evelindev
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Join Date: Mar 2009
Location: Dhaka, Bangladesh
Posts: 11

Cable Rating of Data Center

07/07/2009 1:50 AM

Dear Sir,

We are going to set up one data Center , the electric power load is 220kw, the elcectric vendor offering three solution.

1. 1x 95rm NYY(PVC) power cable x 2run (8 cable goes to basement to 3rd floor , approximate 800m length)

2.1. 1x 185rm NYY (PVC) power cable x 2run (8 cable goes to basement to 3rd floor , approximate 800m length)

3.1. 1x 300rm NYY(PVC) power cable x 2run (4 cable goes to basement to 3rd floor , approximate 800m length)

here sourching voltage : 415VAC (3ph+N)

Please guide me above mention cable rating is ok or not for 15 years life cycle (de-rating, current carying capacity in last year , PVC insulation condition .)

Cable route in internal duct (building cable duct ,here steel ladder carrying the cable ), maximum temperature is 40degC and relative humidity avr 89%.

I am waiting for favour from expert in this fields.

BR/Evelindev
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wareagle
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#1

Re: Cable Rating of Data Center

07/07/2009 11:35 AM

Your amp load is 220 kw(.415 x 1.73 x 0.85 pf) = 360 amps. Rating for you cable in conduit are rated using NEC cable size converted to sqmm.

95mm = 310 amps x 2 cables = 620 amps 185mm = 380 amps x 2 cables = 760 amp

300mm = 460 amps x 2 cables = 960 amps.

VD L-N 2-95 mm = 6.7v 2.5% 2-185 mm = 5.6 2.0% 2-300mm = 5.2v 1.9%

I appears that any of the cables will meet your requirements. Maybe someone can verify my results.
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jack of all trades
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#2
In reply to #1

Re: Cable Rating of Data Center

07/07/2009 4:02 PM

Slight mistake on 300mm2 cable run as only a single cable per phase is proposed not a parallel run of two like the 95mm2 and 185mm2 (so half the current).

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wareagle
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#4
In reply to #2

Re: Cable Rating of Data Center

07/07/2009 4:19 PM

Jack

I am not following you. The OP's post said "3.1. 1x 300rm NYY(PVC) power cable x 2run (4 cable goes to basement to 3rd floor , approximate 800m length)"

OP States power cable x 2 runs. I took this to mean 2 runs of 4 conductor cable. I see not that he states 4 cables to the basements. Little confusing.
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Evelindev
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Join Date: Mar 2009
Location: Dhaka, Bangladesh
Posts: 11
#6
In reply to #1

Re: Cable Rating of Data Center

07/08/2009 2:47 AM

Thanks for give me calculation with cable rating, I have already collected NEC 2008 book, so I will check the cable rating in rm(mm2) . In our country most of manufcture in ISO certified but most of cases they did not tested cable and copper quality is unknown . So please again guide me the de-rating in 15 years in life cycle, in future only 15 % load will be incread . Thanks for co-operation to give me details calculation. BR/Evelindev
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jack of all trades
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#3

Re: Cable Rating of Data Center

07/07/2009 4:05 PM

You really need to indicate just how much future load expansion you are expecting over the life of the installation. All options look fine but if you are expecting your data centre load to double then some cable options will be too small to handle the additional future load.

It's all about future-proofing.

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wareagle
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#5

Re: Cable Rating of Data Center

07/07/2009 4:45 PM

If the PO intended only one run of 300mm instead of 2 then the VD is in error.

Quote "Your amp load is 220 kw(.415 x 1.73 x 0.85 pf) = 360 amps. Rating for you cable in conduit are rated using NEC cable size converted to sqmm.

95mm = 310 amps x 2 cables = 620 amps 185mm = 380 amps x 2 cables = 760 amp

300mm = 460 amps x 2 cables = 960 amps.

VD L-N 2-95 mm = 6.7v 2.5% 2-185 mm = 5.6 2.0% 2-300mm = 5.2v 1.9%"

With only 1 run of 300 mm, the voltage drop would be 10.4 volts.
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wareagle
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#7

Re: Cable Rating of Data Center

07/10/2009 7:53 PM

Quote "So please again guide me the de-rating in 15 years in life cycle, in future only 15 % load will be incread . Thanks for co-operation to give me details calculation. BR/Evelindev"

I would think you need to check with the manufacturer for this information
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PWSlack
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#8

Re: Cable Rating of Data Center

06/16/2023 9:37 AM

The <...elcectric vendor...> can show this by calculation. Pick up the phone, and ask for it!

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Evelindev (1); jack of all trades (2); PWSlack (1); wareagle (4)

Previous in Forum: Wire Sizing and FLA and LRA Motor Ratings   Next in Forum: MCCB Breaking Capacity
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