Are Double throw switches provided with a dual cover interlock that prevents opening the cover when the switch is in either ON position?
Double Throw Safety Switches
Resolution: The Dual Cover Interlock feature for the Double Throw Safety Switches is a Safety Feature to prevent unqualified persons from access to energized components internal to the safety switch.
The Dual Cover Interlock works as follows: When the switch is in either 'ON' position, it prevents someone from opening the switch cover and when the switch is 'OFF' and the cover is 'OPEN', it prevents someone from turning the switch back 'ON'. All the Double Throw Switches that contain a Dual Cover Interlock feature, have a Bypass located on the switch for a Qualified Person to bypass the above features. Either to open the cover with the swith 'ON' or to turn the switch 'ON' when the switch has been turned 'OFF' with the cover OPEN.
A Dual Cover interlock is provided on the below Double Throw Switches:
1) The 30 through 100amp, DT and DTU Series F ONLY Switches.(the bypass is located on the side of the enclosure just behind the operating handle and requires a screw driver to operate)
2) The 82000 NEMA 1 ONLY switches.(the bypass requires the interlock KEY part #190002 and the bypass is located on the side of the enclosure just behind the operationg handle)
3) The 600amp DTU switches. (There is NO bypass to open the cover when the switch is 'ON', so the cover CANNOT be opened with the switch in either 'ON' position. BUT when the switch is 'OFF' and cover 'OPEN', to turn the switch 'ON', the interlock 'defeater' bar must be pushed to allow the switch to be turned 'ON').
A Dual cover interlock is NOT provided on the below switches:
1) NOT available on other 82000 NEMA types.
2) NOT available on any of the 92000 switches.
3) NOT available on any of the 200amp Series E, DTU switches.