Connections, Connectors, and Couplings

DOE-HDBK-1092-2004

In a chassis with ac service connected to it, the grounding terminal of its receptacle shall be

internally bonded to the chassis frame. (NEC 250.146)

If solder is used, the connection of the equipment grounding conductor shall not depend on

solder alone. (NEC 250.8)

The leakage current of cord connected equipment should be very low.

9.5.1.2 CONNECTIONS, CONNECTORS, AND COUPLINGS

Input/output ac power connections to the chassis shall comply with NEC requirements.

The exposed, noncurrent-carrying, metal parts of panel mount connectors operating at 50 volts

or greater shall be bonded to the chassis.

Plugs and sockets for connecting any AC power source shall be NRTL-listed for the application.

(Ref. ISA-S82.01-1992, Section 6.10.3.a)

AC power plugs and sockets shall not be used for purposes other than the connection of AC

power.

Connectors operating at 50 V or greater shall be listed, rated or recommended for their intended

use.

Any connector used to provide power at 50 V or greater shall not allow personnel to make

inadvertent contact with the power source.

If plug pins of cord-connected equipment receive a charge from an internal capacitor, the pins

shall not be capable of rendering an electric shock or electric burn in the normal or the single

fault condition 5 seconds after disconnection of the supply. Plug-in type connectors intended to

be connected and disconnected by hand shall be designed so that the grounding conductor

connection makes first and breaks last with respect to the other connections. [NEC 250.124(A)].

The following applies for all AC power connectors within or external to electrical/electronic

enclosures:

1. There should be no exposed current-carrying parts except the prongs, blades, or pins.

2. The connector shall prohibit mating of different voltage or current rating than that for the

device intended.

3. All connectors must be protected against overcurrent in accordance with their rated

ampacity. (NEC 240.5)

4. Connectors must be NRTL-listed for the application.

5. Use of MS, PT, or other non-approved connectors is not permitted except when justified to

and approved by the AHJ.

If conditions require the use of a non-NRTL listed or labeled connector, such as an "MS"

(military standard pin and socket type) or "PT" (similar to "MS" but smaller) type, for input/output

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