mstrlucky74
Senior Member
- Location
- NJ
When not shown as either how do you determined if it needs to be fused or not? Thanks
Fused & NF Disconnects
- Thread starter mstrlucky74
- Start date
- Status
Off the top of my head, four things come to mind:
Does the downstream equipment require fuse protection.
Are fuses required to address fault currents.
Will a NF disconnect comply with Code (see this ongoing thread: http://forums.mikeholt.com/showthread.php?t=179232 )
Often times if the exact size of the protection is not known (such as HVAC units where exact specs are not provided at initial wiring)
some folks use fusible disconnects as its easier to select the correct fuse than change an existing breaker if necessary)
Does the downstream equipment require fuse protection.
Are fuses required to address fault currents.
Will a NF disconnect comply with Code (see this ongoing thread: http://forums.mikeholt.com/showthread.php?t=179232 )
Often times if the exact size of the protection is not known (such as HVAC units where exact specs are not provided at initial wiring)
some folks use fusible disconnects as its easier to select the correct fuse than change an existing breaker if necessary)
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
The schematic symbols are pretty distinctive from each other. What are you looking at that has them not shown correctly.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If the drawing simply shows a piece of equipment with a symbol for a disconnect I would assume that it's non-fused.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
I don't disagree, but I have seen a LOT of very lazy drafting jobs make it to project specs.
Case in point: All of these are using the symbol for a NF Disconnect, yet clearly, they are not. Luckily, they are labeled...
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mstrlucky74
Senior Member
- Location
- NJ
Yes they usually are..not in this situation. Its a disconnect for a industrial type washing machine(tunnel washer)...60a 480v
RFI...
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Not always true. Some larger units require fuses- for example it will say largest fuse.... In that case fuses must be used
BTW welcome to the forum
I've seen it depicted like that (or like a set of schematic relay contacts) if it is a vacuum or air contactor/switch controlled by external protective relaying
mstrlucky74
Senior Member
- Location
- NJ
- Status