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Fire Pump Disconnect Switch

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Zaster85

Electrical
Jan 18, 2008
4
I have familiarized myself with the NEC about fire Pumps and started to spec. out parts for the electrical upgrade we are doing.

However, part of the code requires that the Pump be lock-able in the closed position. Now, I didnt think this would be a problem, but alas I cant find a disconenct switch which allows this.

Ive looked in the Square D Catalog, but could not find a disconnect switch which is lockable in the closed position. Also did a couple google searches with no luck. Does anyone know a company which sells disconnect switches for fire pumps? If I did miss it in Square D, what category should I look for?

Thanks.
 
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My understanding:

Normally you run your wiring from the service drop area to the FP control system directly, not thru a bunch of interposing disconnects.

Otherwise just fabricate a lock system. Two little "U"s with a rod and a lock.

Keith Cress
Flamin Systems, Inc.-
 
Thankyou for your replies.

To answer the last poster, we are not sending this through several disconnects. The Feeder is spliced upstream from the Main Service Disconnect. This Fire pump feeder then must pass through a Transformer, then goes to a Fire Pump Controller.

We want the disconnect in case the Transformer or anything downstream for that matter needs servicing, not to mention incase the transformer fails.

To the first poster, that unit seems to be a complete package, both disconnect and controller. We are mainly looking for a seperate unit which is only a disconnect switch. We are afraid of disturbing to much of the system (since its grand fathered). If we replace the Fire pump controller, we'd get ourselves into a lot more trouble then the client or ourselves is willing to pay for.
 
Of course it would have to be sized for locked rotor current if equipped with overcurrent protection (which it may have to be for short circuit rating).
 
Well I looked high and low. I couldn't find one either.

On SquareD disconnects there is a large external piece of sheet metal that has a area cut out where you put a lock to prevent the handle from passing. The rest of the arc is solid. All you have to do is drill a single hole thru that, which does not penetrate the box in anyway, to provide the same locking mechanism at the top of the arc where the lever is when the disconnect is ON.

Keith Cress
Flamin Systems, Inc.-
 
Siemens VBII disconnect switches provide an easy modification that can be done in the field which will allow them to be locked closed.

Siemens VBII disconnect link

See note 6 on page 14
 
Thanks everyone, especially Jraef. That should work, now just have to get the customer to agree.

One would think these would be easier to find considering the NEC requires them.
 
Well like I say they are all made almost the same and a drill and about 60 seconds is all it takes. Most electrician would not bother with hunting down one with a 'dimple' in it.

Keith Cress
Flamin Systems, Inc.-
 
I agree with drilling a hole, and most all safety switches I’ve seen are designed with metal to drill, and some are punched to indicate where to drill. BUT, as soon as you drill that hole you void the testing agency approval, the device is no longer listed.
Steve
 
To anyone interested in this, I just got off the Phone with Square D.

ALL Square-D Disconnect Switches (Called Safety Switches in their Catalog) are punched/marked with an area to drill to allow the switch to be locked in the closed position.

They also told me that this modification is allowed and will not violate the UL or any other ratings the box has so-long as its done correctly.

I would recommend calling them for the application you wish to use it for, but this is what their application engineer told me.
 
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