We are trying to replace a 20A 250V single outlet that was installed in 1975. We have tried replacing it with a 15A 120V double outlet. When checking our completed work, the outlet tester read that the wires were reversed. We changed the wiring, and the outlet tester still read that the wires were reversed.
123162
I used the above GFCI/RCD (up to 250v) socket tester on the 240v black and red live wire of the US split phase ac power system. When I connect the ground, all indicator lights (3 red) got on indicating "Live/Grd Reverse, Missing GRD" although it is connected properly.  What is inside the socket tester? Does it have a live and neutral leg such that it should only be used for ac system with polarity? How about if you use it on the red and black 240v phase to phase? Why would all the indicators light become on (3 red lights)?  The following is the specs of it:  Specifications: Brand Name: HABOTEST Color: Black Material: Flame Retardant ABS Plug Type: US Voltage: 48V-250V 45-65Hz RCD Test: >30mA (EU/UK Plug) RCD Working Voltage: 220V±20V GFCI Test: >5mA (US Plug) GFCI Working Voltage: 110V±20V Voltage Measurement: 48V~250V / 45~65Hz    Accuracy: ±(2.0%+2) Working Environment: 0°C ~ 40°C, 20% ~75%RH Storage Environment: -10°C ~ 50°C, 20% ~80%RH Safety Rating: EN61010-1,-2-030, EN61326-1,CAT II 300V Item Size: 62 * 65 * 55mm / 2.4 * 2.6 * 2.2in Item Weight: UK 64g/2.3oz, EU 59g/2.1oz, US 53g / 1.9oz Package Size: 7.5 * 7.4 * 7.3cm / 3.0 * 2.9 * 2.9in Package Weight: UK 90g/3.2oz, EU 86g/3.0oz, US 79g / 2.8oz
10122
Between ground and hot there's approximately 120V as expected.  I had expected the voltage difference between ground and neutral to be 0v, but instead it's 0.4V.  Why would this not be the case?  Is it a hazardous condition?  How would it be corrected?
15015
I have two pieces of single-phase fans and they are literally the same, it is ac motor and whenever I rotate it manually it produce voltage about 160-190vac. I just get the idea that it can be an ac generator, but the problem is when I connect it to 110v-220v cellphone charger, the charger is not working, the voltage drops and the generator seems to run from the voltage itself, I search it and the answer is the backfeeding. I also connect the generator to christmas lights and there is no problem maybe because it has resistors, I also conect Led bulb using an adaptor 110v-220v and the led is blinking(it should not be) and everytime it blinks the generator get a shock, it seems to get backfeed. The other problem is I connect these 2 ac fans and I rotate it to be a generator(160v-190v each) but they seem to be run from the voltage themselves. I had this idea to use a full rectifier, inverter or somewhat to make them a working generator with a stable of 220vac even if using. My ideas/plans (in order):  To stop the backfeed of the generator when using. If there is no possible way to do that then using an inverter is the last option. If ac-dc is the best way then i'll connect dc's from positive to negative, making dc volts step up then convert it to 220v ac. AC-DC-AC in short If no. 2 didn't work, then i'll suppose to make an inverter for each generator making them ac-dc-ac and avr for each to stabilize their voltage.  Please help me guys, I need to make it possible. Another thing I recently know, is it possible to put a ground wire to a single-phase generator to stop getting backfeed instead of transfer switch ? The picture is the single phase motor.
102116
In a moment of cheapness, I decided not to order a 5v to 3.3v level shifter from Sparkfun, but instead to put it together myself.  The  used a  MOSFET, but since I enjoy surface-mount soldering about as much as root canal treatment, I decided to use a  that is through-hole mounted and easily available from my preferred supplier.  The results of this were sub-optimal.  When pulling the 5v line to ground, all was fine - the 3.3v side went to 0.07v.  But when pulling the 3.3v to ground, the 5v line showed around 4.14v (it was otherwise a touch above 5.1v).  On a closer reading of the datasheets involved, as well as the original Philips application note on the subject, I began to come to the conclusion that the gate threshold voltage was the problem.  By altering the schematic and tying the MOSFET's gate to 5v instead of 3.3v, both sides seem to work fine.  Pulling either side low causes the other side to go low.  I'm not, however, at all confident that this is actually a sane thing to do.  My understanding of the original schematic isn't deep enough to form a sensible opinion.  Will this modified schematic work, or are the current good results I'm seeing mere fluke or a precursor to something releasing magic smoke?
27586
Turned on our 2 year old stove (Whirlpool Gold) and heard fizzing noises, then smelled electrical burning. Went downstairs and shut off the breaker (40 amp). That was the only way to get it to stop "fizzing". (6 gauge wire by the way). The range is 240 volt electric 3 wire hooked up to a 40 amp breaker (6 gauge wire). When I took the back panel off the stove I saw exactly where the problem occurred. The black wire was burned, the terminal block was melted, and the inside of the back metal panel that I removed was pitch black in the spot that was facing that area before removal. I removed the stove top and inspected all wires and other electronic components. No problems at all.   So my questions are:    Why did the black wire only, at the terminator block, start burning?  Why did the breaker not pop off?  Is it safe to just replace the terminator block or is this an indicator of a much larger problem?  Is 6 gauge the correct gauge for a 40 amp breaker?
107643
I asked a similar question  about this, but I still don't  quite understand.  Say I grab onto two wires from a standard 120V 20A wall socket. I would fry. I would have 20A at 120 forced on my body.  But, when speaking in terms of circuits, as in my linked question, if I have a power supply outputting 100mA maximum at 5v, for some reason my device only gets exactly what it needs? Why is this?  Most things flow from an area of high concentration to low concentration, taking the path of least resistence. If you connect two wires to a power supply, why don't the maximum number of electrons want to go through your circuit?  If current behaves this way...why do you have to regulate voltage?
41149
I've lost my original power adapter, and I can't find the proper one in any of the stores currently available.  I've HP Compaq 6730b, and as per  it outputs 18.5V 3.5A. However, I've found an older power adapter I have which outputs 19.5V 4.62 A.  So, my question is: how much of a difference between those two it really is, and more importantly, how much of a risk would it be if I tried the power adapter I already have.  P.S. I know pretty much nothing about electricity/electronics.
91944
I asked this question in a convoluted way and didn't get any answers, so I thought I'd ask again and make my question clearer with more images.  I have a 150 amp disconnect at the meter. The box only has the 150 amp disconnect with no additional room (see picture). The 150 amp sub panel inside the house is full.  I'd like to upgrade that box with 200 amp service and some room for additional breakers.  Can I install a 200 amp box like the image below, then add a 150 amp breaker (also pictured) for the 150 sub panel in the house, leaving me with additional space for more breakers?  @Tester101: to answer some of your questions and address your points: 1) The overhead conductors that run from the pole to the meter are adequately sized for 200 amp service 2) The meter and the disconnect are in the same box (as shown), so the issue of adequately sized conductors between the meter and disconnect is minor 3) The grounding/bonding conductors may have to be upgraded, but I'll consult an electrician for that (and all of the issues you've mentioned...I had not planned on proceeding without having a pro review my plans). I really just wanted to make sure I was on the right track re: replacing the meter/disconnect box with a larger disconnect (200 amps), then have a 150 amp breaker for the main subpanel already located in the house. I would then have additional room in the new meter/disconnect box to add circuits as needed
99082
Is it safe to use a 30VDC/1A relay for a voltage of 60V but a current of &lt;100uA? E.g. this one:
67872
I'm not sure what to do here. I just moved into a building and my outlets are all 2 prong outlets. Here is what I know of for sure:   All the outlets are 2 prong outlets The bathroom outlet has the red/black reset/test switch. I'm guessing that means that the building is grounded? The building is off of power lines (not underground)   My fear is blowing my electronics. I am not sure what to do here to properly protect my electronics. I'm hoping that my outlets are grounded-ready or the such, but how can I know? What do I do here?
113032
I have a electric 220 dryer hook up in my kitchen now I want to convert it over to use for a higher grade power supply for my microwave blender and toaster without converting Any wires or touching the  fuse box, is this possible ?
52956
I live in an older house and have some outlets in our kitchen that don't make sense to me. We have one outlet that is tied to a dimmer switch on the opposite side of the room. I can detect that the outlet is hot using my voltage detector (when the dimmer switch is all the way on), but it pulses. I get about 6-7 beeps, then it skips one, beeps 6-7 more times, skips, continue. My GFCI tester shows an open hot. The outlet doesn't work.  I'm not very experienced with electrical work but this sounds highly unusual to me. Where should I start with fixing the issue?
104843
Question says it all really. Based in the UK so mains is 240v and 20 amps. It's a lighting circuit.
108975
I'm trying to figure out how I got a shock from a neutral wire. I didn't think it was possible until I read  on being "in series with the neutral." Here's what happened:  I was disconnecting a ceiling fan remote receiver which has a hot and neutral connection and supplies power to the fan and light kit. The hot wire that supplies the box runs through a single-pole switch, so I shut off the switch and tested with a solenoid voltage meter to make sure it was in the off position. I then removed the wire nuts from the hot and neutral connections. I tested both the hot and neutral bundles with the voltage meter (between wires and the grounded box) and there was no voltage, but there was a small spark when I touched the lead to the neutral bundle. I tested it again and there was no voltage, so I assumed that it was static discharge (I don't know why I did that). So I tested the neutral bundle again, to be safe, and there was no voltage. I started unbraiding the neutral wires and that's when I got a shock.  I couldn't believe it. I got a multimeter out and tested again, but there was zero voltage from the neutrals to ground. I turned the switch back on and tested again (hot to ground and hot to neutral), and the black wire was indeed the hot. Then I realized that there were two neutral wires coming into the box, which seemed odd for a ceiling box with only one load (the fan controller). I tested both neutral wires with the switch on and off (neutral to ground): no voltage on either.  Is it possible to get a shock even though you can't detect voltage from a neutral wire? I think now that "neutral one" came from a mystery load that ran into the box and hooked up to  "neutral two", which runs to the neutral bar. I probably should have tested hot to each neutral separately to confirm this, but I didn't want another shock. Did I complete a circuit when I touched both neutral wires, and that is why I got the shock?
33165
I'm tying into an existing outlet box to provide power for a new electrical outlet. The existing outlet already has 2 lines connected to it - one from "upstream" (to the fuse box) and one downstream to more outlets. The existing lines are connected to the "quick connect" holes in the back of the outlet, leaving 2 open terminals on each side of the outlet. Is it okay to connect the third new line to the side terminals, and the new ground wire in with the other two grounds?   So the new setup would consist of this:   2 lines (2 white + 2 black wires) connected through the backwiring holes 1 line (1 white + 1 black wire) connected via the side terminals (black on "long" side, white on "short" side). all three lines' ground wires pigtailed, with the pigtail connected to the one ground terminal on the outlet.
110198
I have a 20A 240V GFCI breaker in my main breaker box going to a conduit to another breaker box outside. All worked well last summer. Now, when I put any load (weed-eater, light, etc.) on an outlet connected to the outside breaker box, the indoor breaker immediately trips.  I've tried replacing the indoor breaker with a 30A model (it's 10AWG wire) but it still trips under any load.  I've also replaced the outdoor breakers.  I am confused. If this were a short circuit, the breaker would trip regardless of whether there was a load.  Does anyone have ideas on why this is happening and how I can fix it?
39734
Saw the good answer to this question:   But I'm wondering as a followup, since the two primary prongs in an AC mains plug are different, why (in many plug configurations) are you allowed to insert the plug in either direction? Is there ever a case where the appliance cares which line is "hot" and which is "neutral"? Is there ever a case where it's important enough not to screw up?