Well pump with breaker AND fuse?

[jinman]

No problem... you can go listen to 20 minutes of Marie Osmond singing Paper Roses as your punishment...

Oh no! That's a bit severe. How about 10 minutes of Patsy Cline singing Crazy and 10 minutes of I Fall to Pieces because it's a 1st time offense.:laughing:

 

[AlanB]

Richard, I believe as others have said, it is a way of disconnecting the pump without going back to the breaker.

If you were say changing the capacitor in the pump control box, it sure would be handy to just reach over and disconnect power and be able to have your eyes on how it was disconnected. Not that you turned off the breaker, someone went to the breaker panel when your head was in the closet and "fixed" the problem of no water pressure by turning the breaker back on

I have on of the 30 amp disconnects I just put on my pump with 2, 20 amp fuses in it (the tootsie roll style but the same thing)

Mine happens to be in the well house hole, but the point is the same.

If you are there working on the pump, pressure switch, whatever, you need to be able to pull power. You can unscrew the fuses. It is far better IMO than having to go back to the box and flip the breaker (unless you said it and the box is side by side)

Anyway, I think that is more than likely what was handy, as I can identify, I picked up the disconnect at Lowes, thought I looked and thought it could be used with or without fuses, then after mounting the box, realized I had to have fuses to make it work, so off SWMBO went to get fuses from Lowes

My wiring, and I think it is standard is from my CB box, to my disconnect, to my pressure switch, to my pump control box, to my well pump. If you had a two wire pump, you would not have the pump control box part of the equation.

 

[aczlan]

That is odd. They cannot have saved much over using an AC disconnect box (like this or this) so, perhaps it was just what was on the truck that day.

Aaron Z

 

[podagrower]

NEC also specifies that circuit breakers are not to be used as switches.

Breakers used as switches must be "Switch Duty Rated" usually indicated as SWD on the breaker.

And I don't believe you can wire a pump into a "normal" toggle switch. You'd have to have two switches, one for each hot wire, and that would also be against NEC which states the disconnect has to disengage both hot wires simultaneously.

Double pole, and even three pole switches are made for this purpose.

 

[arrabil]

While there are exceptions to the no breakers as switches rule, I'm pretty sure SWD breakers are not allowed in this application.

I did not know about double pole and three pole switches. Never seen one I don't think.

Since you know so much about electric you should answer the original poster's original questions too.

 

[PILOON]

A double pole switch that can take 25 amps costs in the $30-40. range!
In that amperage you are looking at #10 wire and good luck stuffing that into the standard box.

Knife fuse boxes are closer to the $10 range and meet requirements and unless the construction is high ended and maybe cost pluss the electrician will go the cheapest route.

 

[podagrower]

The only reason I can see to have the fused disconnect is-it was what was on the truck. Easiest solution is to keep a spare pair of fuses on hand. Fuses are generally considered to be better protection for motors than breakers. They can be sized a little bit more precisely, and always work (breakers can fail to trip).

 

[_RaT_]

Lots of interesting opinions. I'll add some more 2cents. Fused disconnects are still around although they do not use the screw in fuses anymore. Fuses are for one thing, much more accurate in their rating and ability to be made in many amperage ratings. Some motors may require this kind of protection. As was mentioned, a service disconnect is required by code, it can be many different styles. If its permanent, it needs a hard wired connection, if its portable a plug will suffice. Just because a circuit has a white wire and a black wire means nothing as to its voltage. I often use black and white for a 240V circuit, the difference being is you are required to identify the white wire with a piece of black or red tape in this instance.

You can easily get the 2 pole 30 amp breaker for $15 at places like Home Depot so the comment about them being expensive is not accurate. The exception is the old "Zinsco" style breaker which was bought out by Sylvania and eventually abandoned. Those Zinsco breakers had a hard time not tripping with a high current start up like an AC unit. All breakers today are basically time delay in that they require enough heat to be generated to "trip" the breaker by heating a bi-metallic strip which deforms bending the strip because of the different expansion rate of the two metals. The higher the current above the rated breaker rating, the quicker the trip.

In the case of this well, the first breaker is there to protect the wire, the knife disconnect with fuses is there to first provide a way to safely disconnect the circuit to the pump and its controls for service, simply turning off the main breaker while that would kill the circuit, also invites a problem where someone resets the breaker not knowing it was turned off for a reason. The fuses are there to protect the device. Could a breaker(s) with the appropriate rating be used? Yes, but some manufactuers do insist on fused protection. It is not uncommon to blow only one fuse on a 240V circuit. A low resistance short on one leg can cause it, a fuse with slightly different holding ability and of course, rarely are voltages on each leg identical. The lower voltage leg will have the higher current flow in a given load.

 

[duggo]

You could always use those quick low fuses to protect your Jub tweeters.

Sorry all, inside joke.

duggo aka filmboydoug

 

[CurlyDave]

Here's a picture of the item I'm referring to.

Also, seeing as there are evidently more than one type of screw in fuse, are these the correct ones? (I'd rather find out prior to needing them )

Also, in case I mislead anyone....these are not in any kind of a well house, but rather, in a finished bathroom closet in my basement (full bath & washer/dryer)

Looking at the pictures posted, the fuses in use are 20 A fast acting fuses and the ones in the package are 20 A time delay fuses.

While the 20 A time delays will allow you to get up and running in the case of a nuisance trip, they will not protect your pump as well as a fast acting fuse. If the fuse has blown because of a fault, replacing the the fast acting fuse with a time delay is a good way to create more damage than you started with.

I would get a pair of 20 A fast acting fuses, maybe two pairs to keep on hand. They are cheap enough.

* * * * *

The reason you have fuses in the pump room even though you have a breaker in the panel is that you have a 30 A breaker. I have seen this before on equipment with motors. The motor is specified for no more than a 20 A fuse. The 30 A breaker will allow too much current to flow in some situations, which will result in unnecessary additional damage to your pump, or pump starter. If you have the instruction and the installation manuals for your pump you should find this requirement in there. This is a really good reason to get the correct fuses.

The 30 A breaker is the correct size for the wire you have going to the pump room, but is too large for the specific pump you have installed. Think of it as room for a future upgrade, if necessary.