I’m trying to replace a broken ceiling fan. I shut down the power to that room and took down the old one. Of course, no ground wire.
I did notice turning off that circuit turned off the entire 2nd floor, as well as the Verizon FiOS box (not the set-top box but the other box that the cable from outside connects to) in the basement. The entire house, including this circuit, is a mix of grounded, ungrounded, and GFCI outlets.
If there’s a surge or a short somewhere on that circuit, something else on that circuit should trip the breaker, correct or incorrect?
ETA: I mentioned the Verizon box because it’s always drawing power.
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The question you asked doesn’t really make sense to me.
The circuit breaker in the big box in the basement or garage with all the other breakers does exactly one thing: trips off when excess current flows through it. where 'excess" is defined as above the rating on the handle. Which rating was chosen by the builder based on how thick the wires in the wall are, not on how much stuff of what sorts you have plugged in where. Or wired in like ceiling fans, built-in lighting, etc.
Circuit breakers have nearly zero to do about “surges”.
One way for an overcurrent condition to trip a breaker is a “short”, where the hot power feed is directly connected to the neutral return side or to ground.
There are lots of other ways for power to go wrong or astray that may be dangerous to people or to devices and for which traditional 1970s tech circuit breakers (or earlier fuses) do substantially nothing.
Please try again with whatever is your real concern.
Look in the breaker box and look at the cable (Romex or whatever) that is used with the circuit breaker on this circuit. Is it two wire (black/hot and white/neutral) or three wire (black/hot, white/neutral, and bare copper/ground)? If it is two-wire, then it is likely nothing on that circuit is grounded unless a ground wire from another circuit is used. If it is three-wire, then I am not sure why the fan is not grounded; perhaps someone used a two-wire cable to go from a junction box to the fan.
At any rate, if you’re concerned the fan (and anything else) on the circuit is not grounded, you can install a GFCI circuit breaker on that circuit. It still won’t be grounded, but at least it will offer some shock protection.
As stated it boils down to what type of wiring exists. Another option is armored cable that does not necessarily have a ground wire as the metal sheath was considered good enough. You may not see the difference inside the ceiling box unless you know what you are looking at. If you see the modern plastic romex wires entering the box then it is not armored.Your breaker should trip if there is a short anywhere in the circuit. A slight overload of say 20 amps on a 15 amp breaker could go undetected for some time before tripping. Can you have grounded and ungrounded outlets on the same circuit? Sure if it is an older not up to modern code house. Are you sure the grounded outlets are actually grounded? GFCI outlets will still work on an ungrounded circuit. Use a vom to check for continuity on a dead circuit between the wide blade opening and the round ground plug. Or check for voltage between the small blade and ground on a live circuit. It should be the same as between both straight blade openings.
ETA: conduit / emt could also show no ground wire yet be grounded through the metal pipe.
Outlets in a home are typically “daisy chained” … one piece of romex runs from the breaker box to the first outlet, then another piece of romex to the next outlet and so on … so if you’ve multiple outlets on the one breaker, and if any of the in between outlets doesn’t correctly connect the ground wire, then all the “downstream” outlets will not be grounded …
The ground wire is a safety feature … the current comes in on the hot wire and goes back on the return wire and that’s all you need to run what ever you have connected … the problem is that the neutral will sometimes drift away from ground voltage, and if your device is inside a metal box, this metal box will drift away from ground voltage … allowing for an electric shock if you touch the metal box while you yourself are at ground voltage … thus the third wire in your romex bundle that directly grounds the metal box eliminating the potential for that shock …
With a multimeter or cheap neon tester* you can very easily check to see if there’s actually a ground present. As stated upthread. You don’t necessarily need a ground wire when certain types of conduit are used (and bonded property). With a cheap voltage detector, the the case of a ceiling fan, you’d turn the power back on, and check from black to the metal box. If it lights up, it’s grounded and you’re good.
Sounds like people were upgrading. I’m guessing there’s been several owners. If there’s truly no ground, the three prong outlets may be because that’s all they could buy an the GFCI’s can work with the neutral to offer some protection. But, again, get yourself a voltage detector and see what’s going on. Probe from Hot to Ground and if it see if it lights up. You could also pull the faceplate off and make sure they didn’t just ground it to neutral. Furthermore, you can get outlet checkers that not only check to make sure an outlet is properly wired, but also check to make sure the GFCI snaps off properly. I use them to check my work.
And while I’m thinking of it, don’t forget (or you may not know) GFCI can be wired to protect downstream outlets so, so some of your regular outlets maybe be wired into your GFCIs.
That’s incorrect. Surges are when something too much voltage is shoved into your house, and it happens very quickly. You need a surge protector to protect yourself from that. You can get whole house surge protectors if you want. They’re not that expensive. You said you have an electrician coming. If you want a whole house surge protector installed, call them and let them know so they can do it on the same trip. You can buy everything yourself for about a hundred bucks, so the electrician will probably charge $200-$300 (which is more than worth it if you don’t want to meddle inside your breaker box).
Anyways, a surge is over-voltage getting shoved into your house. Circuit breakers break circuits due to over-amperage. That happens when something inside your house draws too much current. Totally different. Confusing, yes, but different. It’s why too many things will blow a breaker but lightning strikes will fry electronics.
So is half the other stuff that’s plugged in. All your transformers (wall warts), clocks, the stove, microwave, anything with a clock, anything with a memory, anything that can be turned on with a remote, anything with an LED on it etc.
*IMO, everyone should have at least one of those cheap voltage detectors around, and not the non-contact ones, an actual one with metal probes. They can help do a lot of troubleshooting and answer a lot of questions when the problem is “I think this outlet doesn’t work” all the way up to “I’m not sure what’s going on with this switch” or “why doesn’t this electrical box have a ground wire”. On top of all that, you just shouldn’t, ever, touch wires without checking them first.
when I read the OP, the first thing I thought he was asking, is if the various outlets that had GFCI’s on them, would trip if anything on the circuit they were a part of, suffered a short.
And that is a “no.” Outlet GFCI’s don’t detect high current running through the supply wires in the walls, they detect high current going through THEIR OUTPUT.
Depending on the wiring’s age, the armor may not have been used (or intended) as the grounding conductor. Type AC (armored cable, commonly referred to as BX) is only one possible type of armored cable. Early armored cables are also found with either a flat surface on the spiral or a more “lumpy” cable with more pronounced ridges. Both of these normally have cloth or cloth + rubber insulated wires inside, not plastic. The electrical boxes these cables went into may or may not have had clamps at all, and if they do have clamps they may not have been intended to make a solid electrical (as opposed to mechanical) connection. If you’re in the US, type AC cable made in 1960 or later has a thin bare aluminum wire inside the jacket to improve conductivity.
Of course, if any work was done after the original installation / inspection, there is no guarantee that it was done correctly. You can get a an indication of whether or not a ground is present by using a ground impedance tester - if it says there is no ground, believe it. If it says a ground is present, it may or may not be an effective ground and there’s no way to tell unless there is a short to ground, and you don’t want to try that since you can set a fire somewhere along the path.
Over the past decades there have been improvements (I’m tempted to put that into quotes) such as spring clips with copper on one of the “ears” of light switches, as well as teeny-tiny bare ground wires permanently attached to fixtures (I’ve actually seen this on an all-plastic fixture). Part of this was done to help save amateurs from their own work, part of it was done because there are so many permissible methods these days (that light switch ear won’t do a lot of good in a plastic box) and some of it seems pretty inexplicable.
Personally, I like #12 type MC cable in metal boxes, but that’s just me…
Just noticed, if the OPs questionable circuit is not grounded, I don’t think any of the surge suppressors put on the electronics such as the FIOS box will work. I am under the impression they dump the surge to the grounding and not the grounded neutral wire, I could be wrong as I’ve never tested it.
I have never understood the “dumping to ground” thing when people talk about surge protectors. Current is always in a loop; you can’t “dump it to ground.”
For the most part, surge protectors protect against over-voltage conditions. The idea is pretty simple: you stick something between two conductors that has a high resistance when the voltage is low, and “conducts” when the voltage is high. When it “conducts,” it either maintains a constant voltage across it (for MOVs and TVSs) or behaves similar to a short (GDTs).
You can stick these devices between hot & neutral, hot & ground, or neutral & ground. So if there is no ground conductor, you can still stick them between hot & neutral.
If you (any you) buy a generic 3-prong power strip surge protector, did the factory install the MOV (or whatever tech) between hot & neutral or between hot & ground? Or both? How do you know?
If they did install the MOV only between hot & ground and you plug the strip into an ungrounded outlet and a surge comes roaring down the hot side, what happens next? Or what if the surge comes up the neutral line?
That IMO was PoppaSan’s point / question. Not that I have an answer for him or you. But I’m pretty sure that’s the question.
Yes, that was my question. In industry, I typically used the surge protection between hot and neutral as we used multiple power supplies of various voltages in panels sometimes and they were not always grounded. I have a surge protector now on my home PC that detects a ground wire via LED. I recall the 30 word installation “manual” saying it required a grounded circuit to operate.
You have confused two completely different types of current. Standard electricity to power appliances is completely different from a surge. Something completely different from current in a short circuit is a current that hunts for earth ground.
More fundamental electrical concepts apply. If a connection to earth is not low impedance (ie hardwire less than 10 foot long), then that connection is compromised or essentially does not exist. Plug-in protector protectors have a third prong to protect human from a completely different current provide by the AC utility. That plug-in protector does not claim to protect from the other current that actually damages appliances - that is called a surge.
Two completely different types of electricity. The word superposition applies.
Best protection for appliance exists on all circuits - two wire or three. Because best protection from that type of electric current must exist at the service entrance. If that current connects low impedance (ie hardwire has no sharp bends), then that current is no where inside. It does not damage appliances.
If earthed before entering a structure, then best protection already inside every appliance is not overwhelmed. In short, a surge current must connect low impedance (ie less than 10 foot) to earth before entering.
That is completely different from currents that power an appliance; in on one AC wire and exits via another wire.
Always remember numbers. Effective protection always answers this question. Where do hundreds of thousands of joules harmlessly dissipate? A protector is only as effective as its earth ground (which clearly is not a wall receptacle safety ground). Those and more numbers apply.
Second, above is (apparently) irrelevant to the OP’s question. He said “surge”. A potentially destructive surge occurs maybe once every seven years. He had no surges. He may have a short or open circuit. Apparently the safety ground (which is not earth ground) cannot be trusted - requires completely inspection.
Third, a three light tester can never report a good ground. It can only report some defects. Never assume ground is good because a defect was not detected.
