Jeffrey Cheney

Key skill

Panel & Disconnect Termination

This is a skill area on Jeffrey’s resume. It is not a list of gear he has terminated on a named job.

A termination is the point where a conductor becomes part of the equipment. The lug, the torque, the bending space, and the label all have to be right, and the gear has to be in an electrically safe condition before anyone is in it.

What the work includes

  • Match the lug. Copper and aluminum are not interchangeable unless the lug is listed for that metal. Aluminum wants an oxide inhibitor where the listing calls for it, and a conductor brushed clean.
  • Torque. NEC 110.14(D) points terminations to the manufacturer’s torque. A calibrated torque tool, or a listed shear bolt, is the method. “Tight” is not a value.
  • Identify the conductors. On a 480Y/277 system the phase-to-neutral voltage is about 277. Ungrounded conductors need a posted identification method. Brown, orange, and yellow are a common commercial habit for 480 volts. They are not a national color law. Neutrals stay white or gray. Equipment grounds stay green, green with yellow stripe, or bare.
  • Neutral and ground. They meet at the service, or at the bonding point of a separately derived system. In a subpanel they stay apart. A second bond puts neutral current on the equipment grounds. More on the grounding page.
  • Disconnects. A motor disconnect has to be in sight of the motor in the usual NEC 430.102 rule, unless a written exception on that job applies. Fused and non-fused switches are not the same device.
  • Labels. Circuit directory filled in with something a later electrician can use. Arc-flash labels stay readable. Empty directories are how the next person gets hurt.
Panel termination sketch A panel can with three phase lugs, a separate neutral bar, and a separate ground bar. A B C Neutral bar Ground bar Bond only where the system requires it.
Phase lugs, neutral, and equipment ground are three different landings.

Safety

Opening a cover is not the same as an electrically safe work condition. The sequence is lockout/tagout, then a live-dead-live test with a meter rated for the voltage, then the work. Lockout/tagout and electrical safety cover that sequence. Working space in front of the gear (depth, width, and headroom under NEC 110.26) is checked before the gear is set, not after the pipe is in the way.

Wire-bending space inside the cabinet is in Article 312. A conductor forced into a lug at a sharp angle is a future failure.

What's happening now

Terminations on 480-volt and mission-critical gear are a large share of the electrical hours owners are trying to staff.

Code section numbers, energy-code rules, and utility practices change by edition and by city. The authority having jurisdiction, and the employer’s written program, decide what applies on a given job.