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title: Enclosed Switches and Disconnects
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When to use: Enclosed low-voltage (600V and below) safety and disconnect switches and enclosed molded-case switches applied as service, feeder, and equipment disconnecting means in commercial, institutional, and industrial facilities. Covers fusible and non-fusible switches; heavy-duty and general-duty classes and where each is appropriate; horsepower, ampere, and voltage ratings from 30A through 1200A; short-circuit current rating (SCCR), series ratings, and the role of the upstream current-limiting fuse class (Class R, J, T, L) in establishing a high SCCR; number of poles and solid versus switched neutral; service-entrance-rated switches with neutral bonding and equipment grounding; enclosure selection to NEMA 250 (Types 1, 3R, 4, 4X stainless and nonmetallic, 12) by environment; defeatable and non-defeatable door interlocks; provisions for lockout/tagout per OSHA 1910.147 and line-side isolation; visible-blade indication; and the disconnecting means required at HVAC and rooftop units. Listed to UL 98, with enclosures to UL 50 and UL 50E and construction to NEMA KS 1, and applied per NFPA 70 Articles 404, 408, 430 Part IX, and 440.
− Not intended for: Panelboards (see [[syncs/low-voltage-panelboards]]); metal-enclosed switchboards and switchgear; medium-voltage switches and load interrupters above 600V; molded-case circuit breakers applied as branch or feeder overcurrent protection; and automatic and manual transfer switches (see [[syncs/automatic-transfer-switches]]).
+ Not intended for: Panelboards (see [[sync/low-voltage-panelboards]]); metal-enclosed switchboards and switchgear; medium-voltage switches and load interrupters above 600V; molded-case circuit breakers applied as branch or feeder overcurrent protection; and automatic and manual transfer switches (see [[sync/automatic-transfer-switches]]).
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### Switches covered by this standard are individually enclosed air switches, manually operable by an external handle, with all current-carrying parts enclosed, rated 600V and below and 1200A and below. {note}
−### For assemblies that subdivide a feeder into branch circuits with individual overcurrent devices, see [[syncs/low-voltage-panelboards]]. {note}
+### For assemblies that subdivide a feeder into branch circuits with individual overcurrent devices, see [[sync/low-voltage-panelboards]]. {note}
### For drawout power circuit breaker assemblies and higher fault-duty distribution, the switch is part of switchboard or switchgear scope and is not covered here. {note}
## Related Systems {toc}
−### Line and load conductors terminating in the switch shall comply with [[syncs/conductors-and-cables]].
+### Line and load conductors terminating in the switch shall comply with [[sync/conductors-and-cables]].
−### Raceways and conduit entering the switch enclosure shall comply with [[syncs/raceways-and-conduit]].
+### Raceways and conduit entering the switch enclosure shall comply with [[sync/raceways-and-conduit]].
−### Switches serving motor loads fed from motor control centers shall be coordinated with [[syncs/motor-control-centers]].
+### Switches serving motor loads fed from motor control centers shall be coordinated with [[sync/motor-control-centers]].
−### The equipment grounding and any service or system bonding at the switch shall comply with [[syncs/grounding-and-bonding]].
+### The equipment grounding and any service or system bonding at the switch shall comply with [[sync/grounding-and-bonding]].
−### Switch identification and warning labels shall follow [[syncs/equipment-labeling]].
+### Switch identification and warning labels shall follow [[sync/equipment-labeling]].
−### The available fault current used to select the switch SCCR and any series rating shall be taken from the project arc-flash and short-circuit study per [[syncs/arc-flash-study]].
+### The available fault current used to select the switch SCCR and any series rating shall be taken from the project arc-flash and short-circuit study per [[sync/arc-flash-study]].
# Referenced Standards {toc}
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−### The available fault current shall be determined by the project short-circuit study and shall be confirmed for each switch location per [[syncs/arc-flash-study]].
+### The available fault current shall be determined by the project short-circuit study and shall be confirmed for each switch location per [[sync/arc-flash-study]].
### A non-fusible switch carries the SCCR established by its tested combination with a specific upstream overcurrent device, and that combination shall be verified for the available fault current at the switch.
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### The neutral bonding jumper of a service-entrance switch establishes the main bonding connection for the service; its omission leaves the service ungrounded and is a serious safety defect. {note}
−### The Contractor shall coordinate the service neutral bond and grounding electrode connection at a service-entrance switch with [[syncs/grounding-and-bonding]]. {note}
+### The Contractor shall coordinate the service neutral bond and grounding electrode connection at a service-entrance switch with [[sync/grounding-and-bonding]]. {note}
# Construction and Components {toc}
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## Conductor Terminations {toc}
−### Line and load conductors shall be terminated in the switch lugs in accordance with [[syncs/conductors-and-cables]] and the switch manufacturer's instructions.
+### Line and load conductors shall be terminated in the switch lugs in accordance with [[sync/conductors-and-cables]] and the switch manufacturer's instructions.
### Line conductors shall be connected to the line terminals and load conductors to the load terminals, so that the line side is de-energized only by the upstream device and the load side is de-energized by the switch.
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# Identification and Labeling {toc}
−## Each switch shall be labeled to identify its tag, the equipment or circuit it serves, and the source of its supply, in accordance with [[syncs/equipment-labeling]].
+## Each switch shall be labeled to identify its tag, the equipment or circuit it serves, and the source of its supply, in accordance with [[sync/equipment-labeling]].
## Each switch shall receive an arc-flash warning label in accordance with NFPA 70E prior to energization.
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## Stocking spare fuses allows a cleared fuse to be replaced promptly, restoring the disconnect to service without waiting on procurement. {note}