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In Reply to: RE: All can be answered with...... posted by Awe-d-o-file on November 06, 2016 at 06:31:12
Once again. Thank you everyone. I can hear palms hitting foreheads as I struggle with this. :)
I have a Hylelec MS8233D digital multimeter. In the photo, you can see the output pins of the IEC plug. When I measure across "p" and "n" (which I think are hot and neutral respectively) I get .717 volts. Less than 1 v. When I measure from either p or n to earth (here called PE) I get 120v. Is this correct?
Follow Ups:
MannyE,
If you measured without anything being plugged in, you probably measured resistance - measured in ohms, not volts. Without knowing exactly what you measured, and how, it's difficult to say what is going on. Was it actually plugged in when you took measurements?
Was your meter set to volts ( AC or DC )? Or did you just check continuity ( in ohms )?
If it was not plugged in, then you measured something besides volts - there is no voltage if it's not plugged in to the wall. If you were just checking continuity, everything is probably just fine. If it was plugged in and you really did measure 120 volts between N and PE, something is wrong. If it is wired correctly, you should have 120 volts between P and N.
This Post has been EDITED:
When I measure across "p" and "n" (which I think are hot and neutral respectively) I get .717 volts. Less than 1 v. When I measure from either p or n to earth (here called PE) I get 120v. Is this correct?
Humm
If true that would seem to make PE the hot conductor. That doesn't make any sense.
Before you go any further check the power on the end of the IEC power cord only. Use the Link below for the Female IEC connector L, hot, N, neutral, E, for earth ground.
//Here is what you should have at the mains 120V wall receptacle outlet.
From the hot contact (shorter of the two slots) to the neutral contact (bigger of the two slots or "T" slot) you should measure 120V nominal.
From the Hot contact to the "U" shaped equipment ground contact you should also measure 120V nominal.
From the neutral contact to the "U" shaped equipment ground contact you should measure around zero volts. Though this can vary somewhat depending on the connected load on the branch circuit wiring due to VD, voltage drop.
//////
When I said check for continuity I was talking about through the device. From the power in, input end, to the power out, output end.After your last post I discovered the device is not just a fused IEC male connector but actually houses a power switch, fuse, and filter.
I also learned the device is 15 amp @ 120V.
Click on the link below. Does the picture of the IEC power in male plug end of your device look the one in the picture?
If yes notice the L, E, and N?
L = HOT
E = earth ground, safety equipment ground.
N = neutralWith your meter set to continuity or ohms touch one test lead probe to the power in "E" male prong, (the end the power cord will connect) and the other test lead probe to the PE terminal on the other end of the device. The PE terminal should be the one that is at a right angle to P1 and N1. The one in the center between P1 and N1. You should read straight through continuity/OL/short.
Power switch on device must be closed, ON position.
Next touch a test lead probe to the power in "N" prong on the IEC plug. Touch the other test lead probe to the N1 terminal on the other end of the device. You should read continuity/OL/short.Power switch on device must be closed, On position.
Next touch a test lead probe to the power in "L" prong on the IEC plug. Touch the other test lead probe to the P1 terminal on the other end of the device. With the switch closed, on position, you should read continuity/OL/short. Open the switch, turn off the switch, you break continuity. This is the HOT Line.Post back your results.
Edits: 11/06/16 11/06/16 11/06/16 11/06/16
Something is not right - there should be 0 volts between N and PE. P to N should be 120, P to PE 120. Are you measuring voltage with this inlet plugged in to the wall outlet? Be careful!
If it's not plugged in there will be no voltage.
If it is plugged in, are you sure that the outlet and power cord are wired correctly? Don't wire anything to this inlet until you discover what is wrong - it sounds like your ground pin is live - if you ground anything to it that will also become live.
Stereojim,
Here's the schematic for that switch from Schaffner's datasheet. I'm not much with schematics, but it looks to me like PE should be earth ground. Perhaps you're better reading these than me....
Manny, when you're measuring, you have a fuse in place and the switch in the "on" position?
It appears PE is earth ground. Funning way of showing it is straight through though.I wonder if this thing is Listed by any recognized third party safety testing laboratory.
Note:
P (hot), and N (neutral) are both switched with a double pole single throw switch.The fuse is in series with P the HOT, as it should be.
Edits: 11/06/16
I agree PE should be earth, but he said he measured 120 volts between N and PE. Since N is tied to ground, there should not be any voltage difference between the two. Maybe he measured something other than voltage - there might be resistance between N and PE, but there should not be 120 volts. The voltage should appear only at the live wire (P) - the others should be at 0 volts. I'm not sure how he measured this, but something is not right.
Manny,Normal convention for an IEC socket is with the orientation shown, Hot (or Line) should be the tab in the 9:00 position. Ground at 6:00, and Neutral (or common) at 3:00.
You should get 120v between Hot and Ground, and 120v between Hot and Neutral. You should not be getting more than residual voltage between Neutral and Ground (like the .717 volts you're seeing). Sounds to me like PE is actually Hot, and p is ground from what you're measuring. Assume you have a fuse in the tray?
Edits: 11/06/16 11/06/16
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