Fusible vs non-fusible disconnects
Fusible vs non-fusible disconnects
(OP)
what are the primary advantages to using non-fusible as opposed to fusible disconnects? (despite the cost)
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Fusible vs non-fusible disconnects
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RE: Fusible vs non-fusible disconnects
Horrific loss of space in the enclosure with fusible.
Much larger hazard with fusible if no covers available, as the fuse stuff provides an acre of energized metal to touch.
Fusible means energy dissipation in the enclosure, though often not enough to matter.
If the box temperature varies greatly the fuse protection may vary somewhat.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Fusible vs non-fusible disconnects
And the poor wretch who closes into a fault downstream will really thank you for putting fuses in there. (Well, he probably won't actually, but he should).
RE: Fusible vs non-fusible disconnects
There is only one "advantage" so to speak. If you ALREADY have a valid Short Circuit protective Device (SCPD) such as fuses or a circuit breaker somewhere upstream in your circuit, DEDICATED to that single circuit, then you do not need an additional SCPD downstream. In fact it becomes a bad idea to have too many SCPDs in the circuit because you create possible confusion as to which one opened, which increases the risk of a safety mishap.
So an example would be, you have a motor controller circuit. Power for it comes from a distribution board via a properly sized circuit breaker. All wiring is correct for that size circuit breaker out to a local control panel. You are required to have a lockable external disconnect at that control panel, but at that point, fuses would be redundant to the upstream circuit breaker. You don't absolutely need them.
That said, some people may put them in anyway because often times, fuses provide other beneficial capabilities, i.e. current limitation and/or faster clearing for semiconductor devices.
RE: Fusible vs non-fusible disconnects
RE: Fusible vs non-fusible disconnects
RE: Fusible vs non-fusible disconnects
RE: Fusible vs non-fusible disconnects
But hey, it's twice as much as a "courtesy" 5kA untested withstand! (An example of marketing spin 101)
RE: Fusible vs non-fusible disconnects
RE: Fusible vs non-fusible disconnects
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Fusible vs non-fusible disconnects
RE: Fusible vs non-fusible disconnects