Significant Voltage drop to pool equipment

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Old 01-24-14, 02:58 PM
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Significant Voltage drop to pool equipment

I'm trying to help my next door neighbor. Two days ago he asked me to look at his pool pump, said it wasn't turning on, it was installed 15+ years ago and he had no problems till now. The breaker panel has a 2-pole 30A thin Zinsco breaker that measures right around 240 Volts. The wires run around 80 feet to the equipment area and are #12 solid copper (THHN I believe). They run to a pretty heavy duty looking DPST switch, then an Intermatic clock timer, then to the pump motor, 1 HP. The switch was on and the timer switch was off but the timer motor was not turning. Without touching anything I measured 180-185 volts at the hot side of the switch and confirmed that the motor does not run at all. I then removed the timer and the switch, leaving bare wires and measured the same 180-185 volts with no load at all. The visible part of the feed wires appear fine, the clear outer jacket is a bit brittle but the actual insulation is flexible and intact. The motor and pump were installed very poorly (glued solid, no unions) so I haven't tested them. I did take the switch and timer back to my house and connected them to 240V and they both are fine. I have no idea if the feed wires are in metal conduit or plastic as there is a massive bush in the way of the LB . My question is:

Could the breaker or breaker to wire contact cause this?, I had to jam my VM leads way up inside it to measure and the little release tabs for the breaker wire are broken. I hate breakers and outlets with those push in quick connect things. This breaker has no screw connections at all. I wiggled and jiggled the wires but it did not change the low voltage at the other end.

If not, is there any way to test the wires without tearing out this bush and pulling the wire out ?

I remodeled my house 15 yrs ago and I found that the pool equipment wires were pulled through EMT which had been buried and had almost completely rusted to nothing. There has been no rain recently, no quakes, nothing to disturb the wires so I'm at a loss as to why this sudden huge voltage drop.
 
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Old 01-24-14, 04:14 PM
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Where did you put the meter probes when you measured 180-185 volts?

I am guessing that one of the two wires bringing 240 volts to the pool area has been severed, either rusting out or chewed by an animal. But I can't explain where the unchanging 180-185 volts comes from. I was not going to guess phantom voltage because that would go to zero if you connected a load to the suspected wire.

Voltage drop varies with the attempted current draw (in amperes). If you actually have a voltage drop issue, you will measure the full (here, 240 volts) voltage when there is no load.

A loose connection can also produce voltage drop. You would check all junction boxes and outlet boxes along the way for this circuit.

I suggest a load test for each of the two conductors one at a time.

1. Get a long length of single conductor wire for example 12 gauge THHN, long enough to reach from the panel to the pool house. Connect one end to the panel neutral bus.
2. Also at the panel, verify that one of the regular conductors, possibly suspected bad, is connected to a breaker. (Do not unhook or move that wire.)
3. Flip the breaker on. Measure voltage from the breaker screw to neutral. You should measure 120 volts. NOw flip that breaker off.
4. At the pool house, connect the other end of the free long wire and the other end of the regular conductor being tested to the prongs of the plug of an incandescent light fixture with 100 watt lamp.
5. Flip the breaker on.
6. If the light does not come on then stop here. You may have not identified the other end of the suspected conductor down at the breaker box, or the conductor has a break somewhere.
7. Measure the voltage between the light fixture plug's two prongs while the light is on. You should read 120 volts.
7. Repeat with the other regular conductor.
 

Last edited by AllanJ; 01-24-14 at 05:34 PM.
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Old 01-24-14, 06:36 PM
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The breaker panel has a 2-pole 30A thin Zinsco breaker that measures right around 240 Volts.
First of all, Zinsco panels are a known hazard; the owner needs to be considering replacement. Now, exactly where did you measure the 240 volts? Can you provide pictures of the panel with the cover removed?

Zinsco Sylvania Kearney Electrical Panel and Circuit Breaker Hazards, Failures, Inspection, Detection, Repair, Replacement - Sylvania Zinsco circuit breakers and panel hazards
 
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Old 01-24-14, 06:37 PM
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I will certainly give your suggestion a try.
As far as your other comments:
the particular breaker that supplies the pool equipment has no screws, I had to shove the meter probes up into the breaker. that was 240V. the 180-185 was measured in several places:
1 - with everything connected but the timer switch off - at the input of the "disconnect" switch, with the switch off
2 - as above but with the switch on
3 - switch on at the input lines of the timer
4 - switch on, timer switch on - at the output lines of the timer.
note that I still have no idea if the pump motor is completely dead, it seems to do nothing BUT the 180 volts wont even turn the timer gear motor which I am guessing needs only a few milliamps but is clearly marked 208-230-240 VAC
5 - with everything disconnected, measured directly at the wires

The two wires cannot easily be disconnected from the breaker, the red release tabs were broken / missing. It's the only breaker in there that doesn't have screws to clamp on the wire.....

Your #3 has been done and yes, it measures 120 on both sides
There are no junction boxes, all I can see is a small LB from the ground that then has a piece of EMT going through the equipment area wall. It looks like the smallest LB available and would be real hard to get splices there. To really examine it requires a chain saw to remove the massive bush that blocks all physical access. There is no way to even get the lid off the lnb due to the bush.

I was thinking of creating a load using 2 light bulbs in series just for a momentary test. Hook up the switch and feed the output to the bulbs with my voltmeter attached. As it is, either feed wire to the neutral that is also present is around 90 volts. I suppose I could use one bulb and try each feed and the neutral or the feed and the wire you suggest running temporarily.
Thanks for the reply, I'll post back the results tomorrow.
 
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Old 01-24-14, 06:47 PM
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I can do that tomorrow for sure as far as images. the 240 was measured by shoving my meter probes up into the breaker, as there are no screws and the backwards "L" shaped tabs that I saw on other breakers are broken(1) and missing(1). I also measured each breaker leg to the neutral bar and got 120 (at the panel of course). I don't think it matters but a few years ago this guy got one of the very first Chevy Volt cars and Chevrolet paid to have charger service put into his house. It appears that his service wires from the pole were rerouted to a large panel which serves the charger in the garage and a large sub-panel with a 200A breaker that feeds the old house panel. The meter on the original Zinsco house panel was bypassed. I also checked several outlets in his house and all were right at 120V, and he states that no appliances, TV's, computers etc ever have problems. I'll certainly tell him about the hazard.
Thanks

Edit - Yikes there are many references to Zinsco panels as unsafe not just what you posted.
 
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Old 01-24-14, 07:15 PM
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the 240 was measured by shoving my meter probes up into the breaker, as there are no screws
I suspect that eventually you are going to find the connection at the breaker to be the problem.

Chevrolet paid to have charger service put into his house. It appears that his service wires from the pole were rerouted to a large panel which serves the charger in the garage and a large sub-panel with a 200A breaker that feeds the old house panel.
If this Zinsco panel is now being fed from the big new panel, the Zinsco panel is now a subpanel. If that is the case, replacement wouldn't be terribly expensive, just a main lug panel could replace it.

Yikes there are many references to Zinsco panels as unsafe not just what you posted.
I didn't want to scare you since that didn't seem to be the problem he was experiencing, but it is important you tell him about the hazard. I've seen many Zinsco panels fail. Be careful as you work with the breakers, slight movement can cause arcing between the breakers and the thin aluminum ribbon style busbars. If a replacement breaker is required, I can tell you there are some new replacement breakers available, but they are not U.L. Listed. You can find them easily on Menard's website manufactured by UBI as Zinsco replacements and they are pretty expensive. I'd put that cost toward a panel replacement if it were me.
 
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Old 01-24-14, 09:12 PM
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A test light fixture consisting of a board on which you mounted two incandescent lamp sockets in series and put in two incandescent lamps of the same wattage is a good tool to use to test 240 volt circuits with.

The two leads may have alligator clips put on their ends but should not be connected to a 120 volt plug.
 
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Old 01-25-14, 10:47 AM
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I have a single bulb fixture with a cord & plug, I thought Id bring a duplex outlet over and test one side at a time. The plug will let me use my VM easily also with the fixture plugged into the other outlet.
 
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Old 01-25-14, 10:59 AM
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Should I even mess with that breaker - I don't want to make things worse, he can certainly hire an electrician to do that or just replace the whole panel. Would be nice to get the wires out and/or the breaker to examine but I don't want to break anything
 
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Old 01-25-14, 02:28 PM
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Test Results

I connected the test lamp that I already had, which is a single socket and a receptacle. Neutral wire and one hot measured around 85 volts with the bulb off. I tried 30W, 60W and 100W bulbs and the results were all the same: Bulb Off, 85V, Bulb on, no glow and 0V. The other hot leg was the same except it measured 95V with no load. Results were the same with a temporary neutral also. I told my neighbor to call an electrician, I do not feel comfortable trying to yank out the breaker from the panel or the wires from the breaker. The electrician will be here on Tuesday. With all the help from everyone here, I have done all that I feel comfortable doing and I thank you all. I'll post the results after the electrician is there on Tues or Wed. Pictures of panel are attached.

Thanks again
 
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Old 01-25-14, 06:57 PM
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YOu are getting only phantom voltage on both of the lines. The lines at the pool pump are really dead. There are methods to find out how far the lines go before a break has occured, using tone generators made for the purpose.

Perhaps someone did work on the circuit at an existing junction box somewhere in between, or installed a new junction box, and the wires continuing on to the pump were left disconnected.

Are there any wires entering the main panel that should be connected to breakers and are hanging loose? Perhaps someone commandeered the pool pump breaker in the main panel for somethine else and the pool pump circuit was left unconnected there.
 

Last edited by AllanJ; 01-25-14 at 07:12 PM.
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Old 01-25-14, 08:32 PM
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The neighbor says that no one has done anything in many years. The only evidence of the line is all the way at the equipment area and all I can see is an LB coming up from the ground with a stub of EMT attached that goes through the block wall. There is only about 20 feet of soil that the conduit could be buried in, all the rest is concrete/brick. I don't think a tone generator will do much. The wires at the equipment area are orange and there are no other orange wires in the panel. Turning off that breaker removes all voltage from the wires also so I am pretty sure they are correct, also his equipment has been in place for a real long time and this failure just happened. There are two black wires in the panel that go nowhere but they would not reach a breaker. Pic attached.Name:  Panel-3.jpg
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Old 01-28-14, 11:48 PM
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Final resolution

Electrician was there today, he is doing two things. First, remove all the breakers and bus, etc from the Zinsco Panel, then use the existing new sub-panel as the load center and the Zinsco as a junction Box. The bus was pretty burned in 2 places including the pool breaker, which was not easy to remove, the electrician is a pretty big guy, 6'2" or so and he really struggled with those 2 breakers.

Next, run a new PVC conduit to the pool area. The old pool wires could not be moved even an inch, likely because they were put in metallic conduit that has decomposed.
 
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Old 01-29-14, 03:20 AM
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Sounds like your electrician is a good one and averted a possible tragedy with the Zinsco panel before it was too late. Thanks for the update.
 
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Old 01-29-14, 10:16 AM
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The bus was pretty burned in 2 places including the pool breaker, which was not easy to remove, the electrician is a pretty big guy, 6'2" or so and he really struggled with those 2 breakers.
Pretty typical for a Zinsco panel.
 
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