67

This is because removing a device isn't allowed to interrupt grounding connections Removing a wiring device from the circuit cannot break grounding connections, or else you are violating NEC 250.148(B): (B) Grounding Continuity. The arrangement of grounding connections shall be such that the disconnection or the removal of a receptacle, luminaire, or ...


33

Yikes, good find! This is most definitely the reason. The ground and neutral are only supposed to be tied together at the main panel. In this case, instead of only the neutral carrying current, both the ground and neutral will carry it. There is no legit reason that I know of to do this at an outlet. I wonder if perhaps the neutral was open and the ...


33

When or is it NEC code compliant to upgrade a 2-wire circuit, by adding a third prong equipment ground from a nearby galvanized cold water pipe? Never! Article 250.118 of the National Electrical Code lists the approved methods of equipment grounding. Water piping systems are NOT listed there. Metal piping systems within buildings are required to be bonded ...


25

Your house is wired using the EMT conduit wiring method. Individual wires are carried inside metal conduit. The conduit is the ground path. Most commercial and industrial buildings look exactly like this. Since they are individual wires, they are able to use any of 11 wire colors to disambiguate circuits, instead of the usual black white red. If you ...


23

The grounding conductor in an electrical system provides a safe path for fault currents to travel along. It's there to prevent electrocution. No Grounding Conductor Let's say we have a toaster. Inside the toaster are two conductors, a black ungrounded (hot) conductor, and a white grounded (neutral) conductor. To heat the toaster, current flows into ...


23

I am glad you are finding it convenient that some devices allow themselves to also be used as splice blocks. However, that is prohibited for certain types of wires: Any and all ground wires Neutral wires on multi-wire branch circuits That is because it will cause serious problems for other (e.g. downline) loads if those connections are severed due to ...


20

Just some sand paper will be fine. You don't want to use a chemical stripper as it may interact poorly with the copper.


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 ...


17

No -- that bond wire could save your life! It is very important that all non-current-carrying metal, including the cold and hot water pipes, be bonded to the electrical system ground. This prevents highly unpleasant surprises should a wire in the dishwasher come loose and contact a water pipe! Furthermore, this requirement is enshrined in 250.104(A) of ...


17

Someone forgot a fitting Normally, armored cables (like yours) are brought into a box using a fitting designed to clamp the the cable armor, grounding it to the box and also providing a strain relief for the cable inside. Your furnace installer didn't have that fitting on hand, though, so they simply shoved the cable through the hole and shoved a "redhead" ...


17

I think the power guy's assessment was spot-on He said it appeared that the buried cable coming in from the street had degraded or been damaged and that the "hot must have nipped the neutral." What was happening is that the incoming hot probably contacted the ground indirectly via the insulation failing in some fashion. Your neutral bonds with the ground ...


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.


16

Filipino electrical service is a morass. There is some Euro 230V single leg service, and there is some American style 120/240 split phase service. And if those services are wired to Euro or USA standard, they'll be as safe. However, in actual practice, weird things get done in the Philippines. And there is a high rate of electrocutions. This is one ...


14

To answer your first question, no it's not permitted to have a 3 prong receptacle without the ground wire being attached. See some of the other questions explain how you should fix this situation. I believe the short answer is that it should be a 2 prong receptacle (which will be difficult to find and only to be used in grandfathered situations) or you could ...


13

DO NOT connect the ground wire to the grounded (neutral) conductor, as this could lead to current flowing through the body of the dryer (and potentially through you). The installation guide for the dryer will have wiring instructions for both 3, and 4 wire configurations. Check the manufacturers documentation for proper wiring, but I would say the first ...


13

In addition to what @ThreePhaseEel said, the purpose of having two screws on each side is not so that receptacles can be wired in series. While that is allowed, the purpose is for "split receptacle" setups, where only one outlet is controlled by a switch (or each is controlled by a separate switch). This is done by breaking the metal tab that joins the two ...


12

The correct answer is that you cannot install a 3 prong grounded outlet without using a 2 conductor with a separate ground conductor, that's three conductors. I know people cheat and put a wire from the ground screw of the outlet to the metal box and hope that the armor case is firmly connected to the box and grounded at the panel. This is not a good ...


12

Depends what you're trying to protect. If your goal is to protect the oven from ESD (static electricity) damage or lightning-strike damage, or help it receive radio signals, then going out to a ground spike can help you with that. It won't do a thing for human safety, though. To protect humans from electric shocks, you can go one of two ways. GFCI ...


12

The bare copper wires are the ground (grounds are either green or bare wires). You need to add the green wire from the dimmer to this bundle in the wirenut. The white wires are probably the neutral, providing a return from the lamp to your electrical panel. If you had a smart switch that needed a neutral connection, you would connect there. Note: this ...


11

It is extremely unlikely that all three receptacles all have bad grounds. Not impossible, but unlikely. The most likely scenario is that your home was built before grounding became required by code (1962, plus however long it took for your state/municipality to adopt it), and then someone renovating after that time put in 14/2 Romex with a bare ground for ...


11

Burnt wires are usually the result of a loose connection. When a connection is not solid, wires can heat up. This can be an even bigger problem with high amperage devices (heater, stoves, etc.). This likely has been an issue for a long time, and finally reached the breaking point. The problem with overheating wires, is that the issue becomes compounded ...


11

The accepted answer states "it's not permitted to have a 3 prong receptacle without the ground wire being attached." This is incorrect. 406.4(d)2(b) A non-grounding type receptacle(s) shall be permitted to be replaced with a ground fault circuit interrupter type of receptacle(s). These receptacles shall be marked "No Equipment Ground". An Equipment ...


11

In all my years I have never seen a device ground screw rated for two conductors. Even clamp type ground connectors found on GFI devices are only rated for one conductor. You will need to pigtail a single wire to the device. This can be achieved several ways. A green wire nut, a ground crimp, or a standard wire nut are examples.


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

You can't rely on the integrity of the ground/earth on the pipework of the sink. For all you know it could be connected to PVC pipework further down. In the U.K all pipework is meant to be cross-bonded which is then taken to the earthing bar. However in Japan I am unsure if this is what is done. Regardless you should be earthing/grounding it back to the ...


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

The instructions for the fixture are only correct for a metal box. If a metal box was used, the box itself would (should) be grounded. The bracket that holds the light would then be connected to the box, which would make the bracket grounded. Finally the ground wire from the fixture would attach to the bracket, grounding the fixture. In the case of a ...


10

That explanation doesn't really make any sense to me personally. The neutral bus bar in your main panel should be bonded to the ground bus bar so in effect, all neutral wires in your house are grounded. The third prong in a typical three prong outlet is known as the equipment ground. This is a safety feature that should cause your breaker to trip if an ...


10

The neutral and ground MUST NOT be bonded at a sub-panel. They should only be bonded at the main service panel. If you bond them anywhere other than the main service, the neutral return current now has multiple paths, including though your ground wire. You should be able to buy a second bar for the sub-panel if it really is meant to be used as a sub-...


10

The best way to check for the bootleg ground, is to open up one of the boxes and look at how the receptacle is wired. Since the grounded (neutral) and grounding conductors are bonded at the service equipment, they should always be at about the same voltage potential. If you had a long circuit, and an accurate meter, you might be able to measure a slight ...


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