Hot answers tagged

23

The technique is called double-switching. According to this article, on AC equipment the technique is used to avoid dangerous conditions when hot and neutral are reversed, as often happens with outlets that have been improperly wired. It is permitted by this exception in NEC 404.2(B): 404.2(B) Grounded Conductors. Switches or circuit breakers shall not ...


22

There's a rule to prevent that shock In a multi-wire branch circuit (which shares neutral), Pigtail neutrals. This is why: so you can remove any device for servicing without severing the neutral that other hot wires are depending on. Set aside, for now, the fact that this isn't a MWBC and is, in fact, a disaster. Consider the neutral above the ...


21

No, you cannot do this. Assuming the nearby outlet you want to borrow neutral from is on a different circuit, you will be overloading its neutral. Even if it is the same circuit, it's very bad practice to leave broken wiring energized without fixing it -- what if it moves a little and reconnects just enough to arc? Then your house is on fire. However, ...


20

The tester can't tell the difference. One way to look at is that electrically, since neutral and ground are already bonded at one location (normally the main panel), the electrons don't know the difference. But the other way to think about it is to look at what the tester is actually doing. What do the Lights Indicate? These testers are actually 3 simple ...


18

The naked wire is the ground (sometimes colored green) and is not the same as the neutral. Your particular installation requires a neutral so that the switch can be powered without sending power to the load. If there is no neutral in your electrical box it means that the power source (line) does not come into that box and instead you are just switching the ...


18

Power doesn't want to return to earth. It wants to return to source. For natural power, ESD and lightning, yeah, source is earth. However, for human power, source is the transformer or battery. So hot wants to get back to neutral or the other hot. As it happens, there's an equipotential bond to keep the three voltages (240V and neutral in the middle)...


18

Whoever wired this panel simply was not paying attention The installer who wired this panel did not pay attention to the schematic on the label, assuming that removing the bonding strap was enough here. However, the split ground design of these Murray panels means that the left-hand bar is factory bonded to the case, with the right-hand bar being the only ...


16

It's called a bootlegged ground. This is commonly done in older houses that had a two prong receptacle and was updated to a three prong receptacle. The old house didn't have a ground and this tricks the inspector's electric checker, so your house passes inspection.


15

Absolutely not. That sort of thinking works with safety ground, which does not ever carry current, except during a fault condition (and we hope there aren't 2 independent fault conditions occurring at once). However, current flows in loops. Neutral is the normal "return half" of the loop, and it needs to be dedicated to this circuit. In fact, neutrals ...


14

Switches are not circuit breakers (overcurrent protection). They cannot protect wire and do not make it ok to use smaller wire past them. If any 14AWG wire is used, you must downgrade the breaker to 15A, and downgrade the countertop receptacles to 15A. The other wire can remain 12AWG. This will mean it is not one of the two mandatory 20A circuits for ...


14

Probable reason: they made ONE saw assembly and used a motor that could be configured as 110 or 220. For 220 you would break both lines, for 110 you don't need to, but there is nothing saying you can't (so long as your switch breaks both lines together), so it's just easier to have everything the same.


11

This is actually rather easy to fix The problem is that the light on switch 2 was routed using the hot and neutral from circuit/leg 2, while the switch itself is powered by the hot from circuit 2 but the neutral from circuit 1, creating circulating currents that can heat metal parts and cause EMI as well as a Code violation (300.3(B)/310.10(H)). Moving the ...


11

Yes, it will misread. Because magic-8-ball testers are built for one thing: a quick pass/fail test for brand new wiring you just installed. Obviously, in new wiring, you don't have a bunch of the kinds of problems you have in old wiring, like people bootlegging ground off neutral. The device is simply not made to solve those problems. So if you misuse ...


10

Considering there is some amount of either wrong, or maybe just misleading, information regarding your broad question which, in turn, can lead to ambiguities and poor and/or dangerous actions, I, a real electrician, will add my hat in the ring backed by the NEC. Because many people may search and find this post, as it is very generally asked, and in a given ...


10

Based on further conversation.... this is an emergent condition that is trying to kill you. It hasn't succeeded only because the shock path to source is high-impedance and limiting current flow to below 10ma. (if you can feel it, it's at least 1ma). Naturally occurring impedances can change dramatically, so it could turn and kill you tomorrow. You say ...


9

Because the grounding system is a safety system, and is designed to only carry current during a fault. If you use a grounding conductor as a grounded (neutral) conductor, you'll have current flowing on water pipes, faucets, appliance frames, metal electrical enclosures, and anything else that's grounded. Doing this could lead to property damage, injury, ...


9

If you have any #14 wire in the circuit, you have to put a 15 A breaker on it. So, to keep your 20 A breaker, you should use #12 wire everywhere, and run #12 to the switch and lights.


8

A GFCI breaker does not know or care what happens upstream (elsewhere in the subpanel or back at the main panel. All that matters is that neutral and hot are connected to it properly so that it can detect the difference between them. If there is a ground wire going to the protected device then that ground must be separate from neutral until sometime past the ...


8

understand the logic behind Bonding the Neutral and Isolating Ground the green earth ground or bare copper always connects to the metal of the panel box, or any metal that you touch. the [white] neutral only connects [bonds] to the green earth ground connection at the main panel. in any sub panels wired from the main panel you isolate the neutral from ...


7

It's using the earth as a return path You really don't want to do that. Dirt doesn't conduct electricity very well. Your neutral is bonded to ground in your main panel. The power company's transformer also bonds neutral to ground at the pole, and all your neighbors have neutral-ground bonds like yours. The current is trying to return to source (neutral)...


7

Chase down the matching neutral and remove it. Otherwise it will drive you crazy, and be a loose end of wire unaccounted for. What's more, it could wind up still being in use by some other circuit which shouldn't be there. Part of the reason to fully explore an electrical system is to look for surprises. Besides, since all wires must terminate in ...


7

You'll need to find something that doesn't need a neutral, or run a /3 cable to replace the switch loop Unfortunately, the timer switch you have needs a neutral, which your old-style switch loop wiring does not provide. So, you'll either need to find a different switch that doesn't need a neutral, or to replace the existing cable with a /3 cable so that ...


7

Panel issues First, manasshkatz correctly spotted the alien breaker second from bottom on the right side. The lower left breaker is a Siemens QP. Those alien breakers have gotta go. You need "Westinghouse" (read: Cutler Hammer/Eaton) BR/C family, commonly known as BR. The 30A Siemens is a mystery. There's almost no legitimate use for a 30A 1-pole breaker....


7

This is wired as a main panel (not a sub-panel), so they are effectively the same. Best practice is to wire grounds and neutrals separated in case this panel ever needs to become a sub-panel, but what you've got here now is a typical main panel where the neutrals and grounds are intermixed.


6

Replace this panel before it burns your house down! You need a new panel not a new neutral bar, as this panel is trying to cook you, your kids, and your house as I speak. The FPE Stab-Loks are rife with trouble, and as you have seen, will attempt to burn your house down instead of doing their job. In particular, at least one of your breakers is out of ...


6

By US conventions, black should be hot, white should be neutral, and red should be alternate hot. Normally. When you see a switch connecting white and black directly, this is a "switch loop", where hot was brought to the fixture first, then down to the switch; the switched hot is brought back up to the fixture. If they were competent, the electrician ...


6

Don't walk, but RUN to your closest licensed electrician to fix this problem. There is no workaround. It simply needs to be fixed correctly. This is a life-threatening situation. Until you get a contractor out to look at it, avoid all contact with that outlet.


6

To those who know all about MWBCs, this particular case is bizarre, interesting, and falls in the "you learn something new every day" category. Please read carefully and not leap to conclusions. Thank you. OP's comment The circuit breakers on the diagram are not feeding opposite phases, but the same one. means this is a shared neutral which is not a MWBC. ...


6

Do NOT do this. It is wrong in so many ways: Completely illegal from the electrical code standpoint. Using a 120V outlet for 220V application is incorrect and confusing. Mixing 120V and 240V on the same outlet will lead to dangerous mistakes. Redeploying a safety GND line as a Neutral is going to get someone or some equipment fried. Put the house back to ...


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