Fuses for the bay keep blowing

[Vincescoinwash]

I have this real strange issue going on at my 6 bay wash that I can’t seem to figure out, I have had electricians come by and take a look and they don’t seem to have any idea either. Every few months I have a stretch where the fuses for the high pressure motor in one bay constantly blow, nearly everyday, usually we have 20 amp fuses in there, I’ve tried putting in 30 amp fuses to see how they’ll be but yet the still seem to go. The strangest part is that will have four or five month stretches where it will be completely fine. Any ideas?

 

[Twodose]

Are you talking about at the main panel box?

 

[Vincescoinwash]

Are you talking about at the main panel box?

Yes, each bay has their own individual box with the contactor and fuses that power the motor for the bays high pressure. There’s three 20 amp fuses in that box and those are what’s blowing, hopefully what I’m saying makes sense lol, was raised at this wash as it’s a family business so my terminology may not be very proper lol

 

[Twodose]

A picture would help, don't know why there would be 3-20 amp fuses for one motor?

 

[Vincescoinwash]

A picture would help, don't know why there would be 3-20 amp fuses for one motor?

View attachment 66700023269__CA930D4A-5AA2-4DDE-97CF-D0A4839DD599.MOV

 

[HeyVern]

does it blow one fuse, or all three?

 

[Vincescoinwash]

does it blow one fuse, or all three?

Lately, all 3 but typically it’s been one

 

[Twodose]

I PM'd you, check your mail.

 

[Greg_T]

We had a similar intermittent issue, but it tripped the main circuit breaker for the whole bay. It was initially only very rare, then got more common. After much searching, I eventually found a location where a brass pipe manifold was resting on top of a multi-core cable with 24VAC (very poor installation practise, particularly given the rest of the site is really well built). The pipe manifold had worn through the insulation over time, and would occasionally short between wires in the multi-core. I repaired and shrink-wrapped the damaged wires, separated the cable and pipe manifold with rubber sheets and the problem was sorted.

Not sure if this is going to be relevant to your situation, but it might spark (pun intended) some thought that gets you a fix.

 

[2Biz]

Have you tried putting an amp clamp on each leg of the three phase to see if the load is the same?

 

[Vincescoinwash]

We had a similar intermittent issue, but it tripped the main circuit breaker for the whole bay. It was initially only very rare, then got more common. After much searching, I eventually found a location where a brass pipe manifold was resting on top of a multi-core cable with 24VAC (very poor installation practise, particularly given the rest of the site is really well built). The pipe manifold had worn through the insulation over time, and would occasionally short between wires in the multi-core. I repaired and shrink-wrapped the damaged wires, separated the cable and pipe manifold with rubber sheets and the problem was sorted.

Not sure if this is going to be relevant to your situation, but it might spark (pun intended) some thought that gets you a fix.

Not a bad shout! Thanks for sharing, I’ll have to look around and see if there’s any wires rubbing against anything, then again it’s just the fuses not the entire circuit. Still worth a look tho.

 

[Vincescoinwash]

Have you tried putting an amp clamp on each leg of the three phase to see if the load is the same?

Ya an electrician did that and everything seemed alright to him.

 

[Vincescoinwash]

I have this real strange issue going on at my 6 bay wash that I can’t seem to figure out, I have had electricians come by and take a look and they don’t seem to have any idea either. Every few months I have a stretch where the fuses for the high pressure motor in one bay constantly blow, nearly everyday, usually we have 20 amp fuses in there, I’ve tried putting in 30 amp fuses to see how they’ll be but yet the still seem to go. The strangest part is that will have four or five month stretches where it will be completely fine. Any ideas?

expand...

the contactor on the left is for our air dryer, the one on the right is for the pump, the other pumps are behind the other bays???? Not sure how the location of the other pumps is relevant to this situation.

 

[Jsshac]

Is solid or stranded wire used for the 3 phase power? I have never seen all 3 fuses pop at the same time! Technically if one fuse blows the motor starter overload should trip first.

 

[Vincescoinwash]

Is solid or stranded wire used for the 3 phase power? I have never seen all 3 fuses pop at the same time! Technically if one fuse blows the motor starter overload should trip first.
[/QUOTE

Is solid or stranded wire used for the 3 phase power? I have never seen all 3 fuses pop at the same time! Technically if one fuse blows the motor starter overload should trip first.

I believe it’s solid wire. Usually it’s only been one fuse but lately atleast 2 or more have been going at once.

 

[MEP001]

I PM'd you, check your mail.

I'm assuming you gave him your phone number to have him call you?

 

[MEP001]

When you take some photos, try and show everything. I can't tell from your video which contactor the motor goes to. The fuses are obviously in front of the right contactor, so whatever that starts is your problem.

 

[2Biz]

The fuses only protect what's on the load side of the fuse. From the looks of the video, you only have the contactor, overload, and the motor that can possibly be the "Electrical" issue or possibly a loose wire on the load side of the fuses. Even a single lose wire can cause more than one fuse to fail, when the motor is "single phased", current (Amps) go up on the two phases left which can cause the remaining fuses to fail. But the Overload should trip if this were to happen...Unless set too high!? Surprised the control box has both fuses and overloads?

All 3 phase wiring between the fuses and breaker box should be protected by a 3 phase breaker. How many amps is the breaker? The control box shouldn't be fused more than the breaker rating, otherwise the fuses are useless....

For starters, I would turn power off to that bay at the "Breaker Box"...Check supply wires to the fuses to "MAKE SURE" you don't have any voltage before proceeding...If you don't have an ohm/voltage meter, get a good one. and learn how to use it or all your profits will end up in the electrician's pocket. Once you've made sure no power is at the line side of the fuses, Then tighten all the Line and Load wires attached to the fuses, contactor, and even check the overload connections, line and load. Then open the electric cover to the motor and tighten all the connections or check wire nutted connections...Now you've eliminated all possible connection issues.

If you don't feel comfortable doing this, call your electrician back and have him go through the steps above. If all is good, sounds like an intermittent motor issue, which is unlikely, or a possible bypass regulator failing that might be over pressurizing the pump and motor causing an overload. Adding 30a fuses will eventually let you know where the issue is, but the cost to fix will go up!!! Not good practice...

One last thing...Is this the only pump and control box wired like this? If you have more than one, use a clamp meter to check load amps between the different control boxes to see if they are the same.

Other than that, I am out of suggestions....

 

[Vincescoinwash]

When you take some photos, try and show everything. I can't tell from your video which contactor the motor goes to. The fuses are obviously in front of the right contactor, so whatever that starts is your problem.

Yes the fuses control the contactor on the right which runs the pump, the one on the left is for the air dryer.