Disconnect for GROUNDED conductors? When and where is it required?

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mdillonelectrician

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I am reading through 690 and in 690.13 it says you cannot disconnect ungrounded conductors, but then in the exception it says you can only disconnect GROUNDED conductors if you leave it accessible only to qualified persons for the purpose of array maintenance.So my question is when and where is this disconnect required , if at all?Do I have to buy a disconnect for grounded conductors only?Help I'm confused!
 
It is never ever required. Only disconnecting means for ungrounded conductors are required. Disconnects for grounded conductors must be accessible only to qualified personnel because they defeat the ground fault detection and interruption system in the inverter when opened.

Disconnecting both ungrounded and grounded conductors can in theory make it safer to work on arrays while they are being installed or serviced, since (assuming there are no ground faults) a worker cannot get a shock by completing the circuit between an ungrounded conductor and grounded racking. That is why the exception is in there. But I have never worked on a system where such a disconnect was actually installed.
 
mdillonelectrician said:
I am reading through 690 and in 690.13 it says you cannot disconnect ungrounded conductors, but then in the exception it says you can only disconnect GROUNDED conductors if you leave it accessible only to qualified persons for the purpose of array maintenance.So my question is when and where is this disconnect required , if at all?Do I have to buy a disconnect for grounded conductors only?Help I'm confused!
Click to expand...

690.13 does not say that you cannot disconnect the ungrounded conductors.

Article 100..
Grounded Conductor. A system or circuit conductor that
is intentionally grounded.
Click to expand...

III. Disconnecting Means
690.13 All Conductors. Means shall be provided to disconnect
all current-carrying dc conductors of a photovoltaic system
from all other conductors in a building or other structure.
A switch, circuit breaker, or other device shall not be installed
in a grounded conductor if operation of that switch, circuit
breaker, or other device leaves the marked, grounded conductor
in an ungrounded and energized state.
Exception No. 1: A switch or circuit breaker that is part of
a ground-fault detection system required by 690.5, or that
is part of an arc-fault detection/interruption system required
by 690.11, shall be permitted to open the grounded
conductor when that switch or circuit breaker is automatically
opened as a normal function of the device in responding
to ground faults.
Exception No. 2: A disconnecting switch shall be permitted
in a grounded conductor if all of the following conditions
are met:
(1) The switch is used only for PV array maintenance.
(2) The switch is accessible only by qualified persons.
(3) The switch is rated for the maximum dc voltage and
current that could be present during any operation,
including ground-fault conditions.
Informational Note: The grounded conductor may have a
bolted or terminal disconnecting means to allow maintenance
or troubleshooting by qualified personnel.
Click to expand...
 
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