15kV door interlock

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strebej

Member
Location
Neenah, WI
As per code. Do I need to install a mechanical interlock that will prevent the switchgear door from opening and exposing the bus while energized. This is a 15kV switchgear.
 

templdl

Senior Member
Location
Wisconsin
Modern switchgear should not let you open the door with out placing the on/off handle in the off position. Alslit also should prevent closing the switch with the door open. There also should be barriers which prevent direct contact with any remaining live parts.
 

strebej

Member
Location
Neenah, WI
In the past have not installed mechanical interlocks. We design for the use of padlocks on the doors. Also there are barriers in place. I was asked if there is a code in place that covered a required mechanical interlock. I am unaware of any. I just wanted to see if there was something out there that I was missing.
 

SG-1

Senior Member
Are you asking about the front or rear of the gear ?

In the rear there is no expectation of an inner barrier or interlock system. If you open the door expect live bus.

In the front however a screen barrier is our standard.

The only door interlocks I see as standard are on the Glorified Knife Switches ( such as WLI ), they do not allow entry if CLOSED and cannot be thrown when OPEN. That said one side of the switch is still energized after the switch is OPEN.

I will ask, if I remember later today.

I expect either ANSI or NEMA requires this, not the NEC.

Send me a PM as a reminder.
 

steve66

Senior Member
The only door interlocks I see as standard are on the Glorified Knife Switches ( such as WLI ), they do not allow entry if CLOSED and cannot be thrown when OPEN. That said one side of the switch is still energized after the switch is OPEN.

I will ask, if I remember later today.

I expect either ANSI or NEMA requires this, not the NEC.

Send me a PM as a reminder.
I agree, but would like to add I also see this feature on motor control centers.

To me, it almost seems like a no-brainer that a 15KV switchboard would have a door interlock. Especially since they seem common on lower voltage equipment. But of course things aren't always as simple as they seem. Maybe there is more of an expectation that 15kv gear is only accessible to qualified people.

Anyhow, a couple of other places to look for requirements might be: OSHA, NESC, NPFA 70E, UL, IEEE, or Factory Mutual. (Not sure if UL lists HV stuff??)
 
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