Connection of Capacitor

[jcross]

Our installers are in the process of connecting a 100 HP motor to a MCC unit. Our standards call for a Size 4 starter, 2/0 cable and 150 Amp fuse and a 15 KVAR capacitor. The capacitor is to be connected to the downstream side of the overloads. The starter is supplied with a mechanical lug that is rated for 1 2/0 conductor. The 15 KVAR capacitor is rated at a little over 18 amps line current which would require a # 10 conductor. I would think a double barrell lug would be required here in order to comply with 110.14A. Anybody ever run into this situation and if so what is the best practice for connecting the capacitor to the downstream side of the overload??

 

[jim dungar]

Re: Connection of Capacitor

You need to create a proper tap connection (maybe even including overcurrent protection). Simply jamming the #10 wire into a connector rated for a single conductor is not allowable per the NEC as you noted.

Why are you putting the capacitors after the overload? This location, while maybe saving a disconnect switch, does require the motor OLs to be resized. Many NEMA Size 4 starters have provisions for adding a lug for capacitors.