Hi. I recently made PC for my brother-in-law and he was kind of happy at first. The thing is that it broke up 3 times. The first it was only the power supply. It didnt worked at all. The second time they told me the computer reseted everytime they put a DVD after a couple of hours and then after a few days the PS broke donw.

The third time, i went to his home and notice that the UPS, (APC 350) showed the "Building wiring fault" light on. I investigated further and found out that it can happen by 3 things. 1.- because the A/C polarity is reversed. 2.- because it doesnt have any ground. 3.- i really didnt understand anything... Lol!!

So i took his PC home and the PS, the video card, the Dvd burner were not working. I change everything and the computer worked fine again so i left it on for 2 days, watched Friends season 3-6 and burned a couple of dvds and cds and it worked great. I know i have a decent A/C current and polarity and using a good UPS. Im afraid that if i took the PC back to my bro its gonna do the same thing.

My question is, is there a way to check the correct polarity? or to trouble shoot his A/C outlet. I know his aparment has only two circuits so that has to mean something. cause he is using a microwave, a TV and the PC in the same circuit. Oh i also tried with a multliple A/c connector that has two lights. One that says that "Building wiring fault" (and light is on), and a "ground" light (its off)..

So i know im not an electrition so im asking if anyone can help with this... I need to troubleshoot this so i stop paying for more PC parts... Any help will be gladly appriciated.

Thank you in advance....

You can get an AC line tester at places like Radio Shack. Plug it into the wall socket and see what it says. I can't tell if that's what you've tried already or if the error is coming from the UPS.

If the AC line tester shows a wiring problem then call an electrician.

yes, just to inform you guys that the polarity was inversed and it had no ground on the wall socket.

Thank you guys . tnx to you all i now know how to troubleshoot this type of things...

Ah! I thought so.
Thanks for the update.

And you didn't electrocute yourself like some thought you might!
Did you copy the relevant post(s) before they were deleted?

I do not condone encouraging the inexperienced to dabble with household electrics by instruction from afar, any more than I would on gas fitting. As an engineer this is probably because I've seen far too many unfortunate statistics.

However I am very pleased to hear that the outcome was successful and hope you made a good safe job of the reconnections.

DerekW

I do not condone encouraging the inexperienced to dabble with household electrics by instruction from afar, any more than I would on gas fitting.

While I wouldn't advise this guy to try rewiring the place himself, it's certainly perfectly safe to plug in a commercially-made device with lights to indicate problems like Hot/Neutral swapped and Open Ground. The original electrician should have his private parts hooked up to the mains for doing that!

Whenever you have a "professional" electrician do wiring work, always check their work afterwards with such a test device. You'll be amazed how often they screw up! And some will actually tell you that you don't need a ground, or polarity doesn't matter, or you can put the whole kitchen on one 15A circuit! Squawk to the code enforcers and the state licensing boards if you get this.

GaPeLo didn't specifically say whether there was a ground wire in the wall box, but if there was the wiring was okay to the box, but someone at some time replaced the wall socket fixture or rewired it and didn't wire it up right or some fool didn't wire it right in the first place - very common, despite the fact there is usually very clear labelling on the device itself. The original electrician or who ever wired it has no control over what someone else does later.
It isn't a matter of whether one is experienced or not, or trained or supposedly professional or not - it's a matter of having the competance to do the task properly.

Phil

Re your quote. I have no problem whatsoever with the poster using a tester as given in response #1.

I was referring to two very lengthy posts from "Tubesandwires" which were removed by the webmaster or moderator (and rightly so) because they were way outside the remit of a computer forum.

What I didn't condone was giving detailed multimeter checks and socket rewiring instructions to a poster (from afar) who at the outset said he had no electrical knowledge. They also happened to contain some dubious explanations and safety guidance was inadequate.

Just because it happened to work does not necessarily mean the job was done properly. We have no idea whether the connections were made securely and safely or not. I would also be interested to know how Tubesandwires measured the competence of the poster before advising (as per his stated criterion in #6).

As an aside I hope the poster tested the other sockets after his fix. If any were hooked up to the one in question then there is quite a possibility that other sockets will now be reversed instead. It all depends on exactly how the reversal was fixed (all wires or just one pair) because there was no guidance given about handling this possibility.

DerekW

"I would also be interested to know how Tubesandwires measured the competence of the poster before advising"

One can never be sure, of course, but in the first post and other posts since deleted, GaPeLo had made some observations and noticed some things others would probably have not made or would have missed observing. I figured he could handle some instructions. Just because he didn't previously know what household wiring was about doesn't make him incapable of learning how to check it out or correct it without electrocuting himself.

"I was referring to two very lengthy posts from "Tubesandwires" which were removed by the webmaster or moderator (and rightly so) because they were way outside the remit of a computer forum."

It was mostly in one post actually. The second part was about how our own house is wired and how that relates to later standards.
Justin contacted me about those, and although I then offered to add more warnings to it when I saw the message, he already had deleted them, temporarily forgetting he had added the Edit feature. Actually, he deleted everything after response 1 at the time.

"What I didn't condone was giving detailed multimeter checks and socket rewiring instructions to a poster (from afar) who at the outset said he had no electrical knowledge. They also happened to contain some dubious explanations and safety guidance was inadequate."

That's a matter of opinion, and the posts are no longer here for others to examine. I felt there was more than enough detail in my first longer post to avoid him getting himself in trouble, or anyone else who read it who had any sense at all. I am a Journeyman carpenter and in my work I have had to keep track of whether other trades are doing what they are supposed to be doing right, or whether existing wiring has been done right, so I have a guide to local residential electrical requirements I have consulted frequently. The standards in Canada and the US are virtually identical. Checking out one wall socket fixture is simple in comparison to the stuff I have had to check on.

Obviously from the flack I have received about this AC wiring subject I will think three times before considering posting similar again on this site.

Well, the only reason I raised all this again was your unfortunate crack "And you didn't electrocute yourself like some thought you might", then followed by Phil who thought I meant you had to be an electrican to use a socket tester - a misunderstanding brought about by the vanished posts to which I was actually referring.

Maybe the poster did a good job, maybe not, who knows. It's just that when he purchased a multimeter in mistake for a socket tester it raised alarm bells with me (as it would with any other responsible electrical engineer), which I think were understandable whether justified or not.

There's little point raking through "all" the points yet again unless you wish but, as an example, I felt it a bit off to just suggest a wall socket ground connection could be made to a cold water pipe (certainly scorned at in the UK anyway) without any mention of conductor size and the fact that it should be cabable of carrying the full fault current. I trust he didn't just grab the nearest bit of flex otherwise he or others might still get electrocuted sometime.

DerekW

"...when he purchased a multimeter in mistake for a socket tester..."

It was I who mistakenly thought he did. He said in a later post, which was deleted, he already had one.

"....a wall socket ground connection could be made to a cold water pipe (certainly scorned at in the UK anyway) without any mention of conductor size...."

I also suggested he could run a ground to another wall socket that has a proper ground wire, mentioned almost every time the ground must be solid 14 gauge copper if the wall wiring is copper, solid 12 gauge aluminum if it is aluminum, and to NOT use (typical fine) stranded wire for the wall box wiring. Running a wire to a fully grounded metal cold water pipe via the proper wiring clamp meant for that (I mentioned that twice) if that's the easiest choice in the circumstances is still okay here for an individual circuit, it just is no longer acceptable for the ground for the main panel.

Fine, I accept that discussing posts that no longer exist can lead to confusion and am happy to leave it at that....

In the UK we have grounded both lighting and power to the main panel for many years, the latter being earthed at the sub-transformer star point (which I mentioned in another deleted post).

This eliminates relying on the plumber for joints which are intended for electrical safety. We also find an increasing use of plastic plumbing (inside and out) and I doubt I need to babble on about the ramifications of that.

We do in fact additionally "bond" incoming water & gas pipes and certain metalic building structures to the main source earth, against the possibility of these becoming live (hot, I think you say). In this respect our regulations are very extensive where bath and shower rooms are concerned.

Some of these difference might be because with 230V supplies we have to be a bit more fussy.

DerekW

I appriciate all ppls help. tnx to the comments and sugestions of everyone i found out the problem. The first thing i done was to go to home depot and bought myself one of those 3 plug testers. and yeah the first error it marked was that the wall socket had now ground. No big risk there!! Then my bro hired an electritian to fix the problem. Then he was the person who found out about the reverse polarity.

Its nice to know a little bit about everything to become a good PC tech. I want to become a good PC tech!! and experience will teach me that. I also bought some safety gloves and googles for using my multimeter. I asked the radio shack guy for some safety things and instructions on how to use safely the multimeter. so i thing i was preety safe when using it.

I thank Tubesandwires for helping me understand basic wall socket connections. now, I least i know how to defend myself from clients when they tell me that the computer I fixed is wrong, but then you get the oportunity to go to there homes (check the wall socket) and prove them wrong.

I thank everyone for there help once again, and if i can be of any other assistance please let me know...

And yeah Tubesandwires i printed the whole thing... Lol!!

GL everyone...

All credit to Tubesandwires on this post obviously.

As you have a multimeter do a bit of googling and you'll learn plenty on how to get the best out of it. Always leave it switched to the highest voltage (Volts) setting after use because there are then few places where you can probe with it and come to grief if you should forget to reset it first.

Take extra care with current settings (Amps) because you must understand how to connect "in series" otherwise there could be a loud bang and and a multimeter fry up - not nice.

Similarly there is a lot of stuff out there about electrics (AC being a good bit deeper than DC if you take it very far). Keep safety well to the forefront in your learning when it comes to mains electricity because although things might work they may not necessarily be safe. If in doubt seek hands-on advice from someone who knows.

Nice neat looking joints with the cable insulation going right up to the connector is a good simple basic rule and don't forget to "dress" all cables and use sleeved grounding wires to make sure nothing touches together and causes fireworks.

Good luck with it all and nice to hear you are eager to learn - it is important to "understand" before you "do".

DerekW

GaPeLo
Thanks for posting again with those updates.
You're welcome.

Derek
As usual your responses are well put together and I appreciate them, even if I don't always agree.

Thx Tubesandwires.

I guess the common interest can provoke different views, although this was more political (small P) than technical - apart from the inevitable USA/UK differences.

That's forums I suppose but I'll try my best to keep things on an even keel in future.

DerekW

The first thing i done was to go to home depot and bought myself one of those 3 plug testers. and yeah the first error it marked was that the wall socket had now ground. No big risk there!! Then my bro hired an electritian to fix the problem. Then he was the person who found out about the reverse polarity.

I'm surprised that the outlet tester didn't also pick up the reversed polarity. Have you tested the outlet since the electrician worked on it?

Just for the record, modern outlets have two different sized prongs (blades) -- the fatter one is the neutral and the skinny one is the hot (in the US, anyway). This forces a plug to be inserted in only one way. I hope the electrician wasn't ignorant or confused and reversed a properly polarized outlet!

Phil Perry
This is a relatively old thread on this high volume site. There may be few if any including GaPeLo that still have it in their MyComputing.Net list.

"I'm surprised that the outlet tester didn't also pick up the reversed polarity."

It probably did, if it's one with three leds.
There were a bunch of posts formerly between response 1 and 2 that were deleted by the webmaster, some of which were mine and GaPeLo's. From his descriptions I guessed he had both reversed nuetral and hot, and no ground at the outlet. I told GaPeLo how to check for those with a voltmeter, etc., but the webmaster and others thought I shouldn't do that so the webmaster deleted my descriptions, amongst other posts.

The wall outlets in the USA and Canada have had two different sized slots for hot and nuetral for a long long time - at least since WW2 if not before that - even old ones that had no hole or connection for ground. What hasn't been around for all that long is the two blades of the plugs being one wider than the other. That wasn't done before the 70s or so, but it's very common if not mandatory for new stuff now. In any case, a grounded plug, which must be used for a computer PS, doesn't need one blade wider than the other because it can only plug in one way - it's only two prong plugs that need that.
GaPeLo's problem was probably caused by some amatuer installing or replacing a wall plug and improperly wiring it - the wiring to the box the outlet is in may be fine.
In most places in Canada and the US replacing your own wall outlet (duplex if it's two in one) or light fixture, etc. is allowed without you needing to have an electrician do it, however unwise that may be.