[RE-wrenches] 2014 NEC 705.22 disconnect for inverter capable of being locked

August Goers august at luminalt.com
Thu Apr 28 15:11:25 PDT 2016


Hi Wrenches,



We have a particular plan checker who wants us to provide a *lockable* AC
disconnect for our inverter output circuit. His particular issue is that he
wants the locking mechanism to be installed and on site. Here is a little
NEC background info:



2014 NEC 705.22 Disconnect Device

The disconnecting means for ungrounded conductors shall consist of a
manually or power operable switch(es) or circuit breaker(s) with the
following features:

(1)    Located where readily accessible

(2)    Externally operable without exposing the operator to contact with
live parts and, if power operable, of a type that could be opened by hand
in the event of a power-supply failure

(3)    Plainly indicating whether in the open (off) or closed (on) position

(4)    Having ratings not less than the load to be carried and the fault
current to be interrupted. For disconnect equipment energized from both
sides, a marking shall be provided to indicate that all contacts of the
disconnect equipment might be energized.

*Informational Note to (4): In parallel generation systems, some equipment,
including knife blade switches and fuses, is likely to be energized from
both directions. See 240.40.*

(5)    Simultaneous disconnect of all ungrounded conductors of the circuit

(6)    Capable of being locked in the open (off) position



NEC 110.25 Lockable Disconnecting Means:

Where a disconnecting means is required to be lockable open elsewhere in
this Code, it shall be capable of being locked in the open position. The
provisions for locking shall remain in place with or without the lock
installed.



Many times we are using a standard back-fed circuit breaker to comply with
705.22. Then we can supply a handle padlock attachment such as the one
shown for Square D:



http://static.schneider-electric.us/assets/pdf/retail/QO-and-Homeline-Accessories.pdf



Does anyone else have experience installing these breaker handle padlock
attachments? My concern is whether we can find them for all of the old
types of breakers that we have to deal with. Also, our plan checker is
requiring that this handle padlock attachment accessory is installed at the
time of our inspection. Is anyone else dealing with similar issues?



Best,



August

Luminalt
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