Cable Tray Size as Per National Electrical Code

Cable Tray Size as per National Electrical Code-2002. Article 392 (I) No of Multi core Cables Cabl es less than 2000 volts in the Cable Tray (A) 4/0 AWG/c!ill ("20 #$%!!) Cable or &ar'er Cables 

The laer cable tray Tray tray Tray must hae an inside aailable !idth e"ual to or #reater than the sum o$ the diameters o$ the cables% !hich installed in a sin#le layer.

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#oli botto! cable tray the tray  the sum o$ the cable diameters is not to e&ceed 90' o$ the aailable cable tray !idth. (*) Cables #!aller Than 4/0 AWG/c!ill AWG/c!ill ("20 #$%!!)

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&aer Ty+e Cable Tray The Tray The total sum o$ the cross-sectional areas o$ all the cables to be installed in the cable tray must be e"ual to or less than the allo!able cable area $or the tray !idth% as per $ollo!in# Table. Table.

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#oli *otto! Cable Tray The Tray  The allo!able cable area is reduced by 22'. Insie ,ith of Cable Tray

Allo,able Cable Area #$%inch (#$%!!)

( inch )*+2.+mm,

 S".inch )+*( S".mm,

9 inch )22/.(mm,

*0 S".inch )(+* S".mm,

*2 inch )30./mm,

* S".inch )9032 S".mm,

*/ inch )+.2mm,

2* S".inch )*3+/ S".mm,

2 inch )(09.(mm,

2/S".inch )*/0( S".mm,

(C) 4/0 AWG ("20 #$%!!) or &ar'er Cables Installe ,ith Cables #!aller than 4/0 AWG ("20 #$%!!) 

&aer Ty+e Cable Tray The Tray  The ladder cable tray needs to be diided into t!o zones )a barrier or diider is not re"uired but one can be used i$ desired, so that the No. 0 and lar#er cables hae a dedicated zone% as they are to be placed in a sin#le layer.

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 A direct direct method to determine determine the correct cable cable tray !idth is to $i#ure the cable cable tray !idths re"uired $or each o$ the cable combinations per steps )2, 1 )3,. Then add the !idths in order to select the proper cable tray !idth. !idth .

(-) Multi conuctor Control an #i'nal Cables .nly 

&aer Ty+e Cable Tray A Tray  A ladder cable tray containin# only control andor si#nal cables may hae +0' o$ its total aailable cable area $illed !ith cable.

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#oli *otto! Cable Tray hen Tray  hen usin# solid bottom cable tray% the allo!able cable area is reduced $rom +0' to 0'. 0' .

(II) No of #in'le conucto con uctorr Cables  2000 volts in the Cable Tray (NC132%"2) 

 All sin#le conductor conductor cables to be be installed in the cable tray must be lar#er than *0 A )+3.+ S".mm, and not to be installed !ith Solid Cable Tray. (A) "000 c!ill (00 #$%!!) or &ar'er Cables

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The sum o$ the diameters )Sd, $or all sin#le conductor cables to be installed shall not e&ceed the cable tray !idth as per $ollo!in# Table. Insie ,ith of Cable Tray

Allo,able Cable Area #$%inch (#$%!!)

( inch )*+2.+mm,

(.+S".inch )*9 S".mm,

9 inch )22/.(mm,

9.+ S".inch )(*29 S".mm,

*2 inch )30./mm,

*3 S".inch )/3/ S".mm,

*/ inch )+.2mm,

*9 S".inch )*22+/ S".mm,

2 inch )(09.(mm,

2(S".inch )*( S".mm,

30 inch )(2mm,

32.+S".inch )209(/ S".mm,

3( inch )9*.+mm,

39S".inch )2+*(*S".mm,

(2) 20 c!il ("20 #$%!!) to "000 c!il (00 #$%!!) Cables 

The total sum o$ the cross-sectional areas o$ all the sin#le conductor cables to be installed in the cable tray must be e"ual to or less than the allo!able cable area $or the tray !idth% as #ien in $ollo!in# Table Insie ,ith of Cable Tray

Allo,able Cable Area #$%inch (#$%!!)

( inch )*+2.+mm,

(.+S".inch )*9 S".mm,

9 inch )22/.(mm,

9.+ S".inch )(*29 S".mm,

*2 inch )30./mm,

*3 S".inch )/3/ S".mm,

*/ inch )+.2mm,

*9 S".inch )*22+/ S".mm,

2 inch )(09.(mm,

2(S".inch )*( S".mm,

30 inch )(2mm,

32.+S".inch )209(/ S".mm,

3( inch )9*.+mm,

39S".inch )2+*(*S".mm,

() "000 c!il (00 #$%!!) or &ar'er Cables Installe ,ith Cables #!aller Than "000 c!il (00 #$%!!)

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The total sum o$ the cross-sectional areas o$ all the sin#le conductor cables to be installed in the cable tray must be e"ual to or less than the allo!able cable area $or the tray !idth% as #ien in $ollo!in# Table Insie ,ith of Cable Tray

Allo,able Cable Area #$%inch (#$%!!)

( inch )*+2.+mm,

(.+S".inch )*9 S".mm,

9 inch )22/.(mm,

9.+ S".inch )(*29 S".mm,

*2 inch )30./mm,

*3 S".inch )/3/ S".mm,

*/ inch )+.2mm,

*9 S".inch )*22+/ S".mm,

2 inch )(09.(mm,

2(S".inch )*( S".mm,

30 inch )(2mm,

32.+S".inch )209(/ S".mm,

3( inch )9*.+mm,

39S".inch )2+*(*S".mm,

(4) #in'le Conuctor Cables "/0 (0#$%!!) to 4/0 ("20#$%!!) 

These sin#le conductors must be installed in a sin#le layer.

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Note4 5t is the opinion o$ some that this practice may cause problems !ith

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To aoid these potential problems due to unbalanced olta#es% the indiidual conductors $or this type o$ cable tray !irin# system should be bundled !ith ties. The bundle should contain all o$ the three phase conductors !ith the neutral i$ used. Cable Tray ,ith #in'le conuctor #i5e *+2mm

22/mm

30mm

+mm

*0A )+0S".mm,

*0

*+

20

3*

20A )0S".mm,

9

*

*9

29

30A )9++0S".mm,

/

*3

*

2(

0A )*20S".mm,

/

*2

*(

2+06cmill )*20S".mm,

**

*/

2

(09mm