Motor terminal box requirement

[leeborne]

The distance between the shortest terminal point (u) to the top of the motor terminal box for my chiller is 390mm. But my client is saying the minimal requirement cross connection of 7.2kV high tension cable is 450mm. Cable is 3-core and using 120mm2 per core cable. Starting method is Direct on line. Brand of cable is Raychem.

Can anyone help to advise on the regulation and reasons for this distance. Thank you.

 

[electricpete]

NEMA MG-1 2003
"20.26 MOTOR TERMINAL HOUSINGS AND BOXES
20.26.1 Box Dimensions
When induction machines covered by this Part 20 are provided with terminal housings for line cable
connections,1 the minimum dimensions and usable volume shall be as indicated in Table 20-3 for Type I
terminal housings or Figure 20-3 for Type II terminal housings.
Unless otherwise specified, when induction machines are provided with terminal housings, a Type I
terminal housing shall be supplied."

Table 20-3 "TYPE I TERMINAL HOUSING: UNSUPPORTED AND INSULATED TERMINATIONS"

Figure 20-3 - "TYPE II MACHINE TERMINAL HOUSING STANDOFF—INSULATOR-SUPPORTED INSULATED OR UNINSULATED TERMINATIONS"

It looks to me like Type 1 is default. It allows smaller distances but requires insultated terminations (like Raychem tape). If Type 2 is used with larger clearances the terminations do not have to be insulated.

The content of the figure and table is a little to much to describe here. I'm not sure if you are even dealing in Nema equipment or whether or not insulated terminations.

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[jbartos]

Suggestion to leeborne (Mechanical) May 6, 2004 marked ///\\The distance between the shortest terminal point (u) to the top of the motor terminal box for my chiller is 390mm. But my client is saying the minimal requirement cross connection of 7.2kV high tension cable is 450mm.
///Contact the cable manufacturer for the shortest cable length for this jumper run at 7.2kV.
A concern is with the cable insulation integrity when it comes to a very short run. Imagine for ecample 10mm run instead of 390mm run.\\ Cable is 3-core and using 120mm2 per core cable. Starting method is Direct on line. Brand of cable is Raychem.
///Contact the Raychem tech support.\\