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Safety: testing Electrical outlets

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  • mhuss
    replied
    The original link is now broken, but Wayback Machine to the rescue:
    https://web.archive.org/web/20170224...esting-exposed

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  • DRH1958
    replied
    As a commercial electrician for 31 years, I had numerous service calls to fix improper repairs done by unqualified personnel at various places. They had someone who said they could fix it. Well they couldn't and they ended up calling a qualified electrician to do it right. So don't forget that venue owners are in the business to make money so try to fix things themselves. It costs money to call someone who can do things right. So don't rush to judgement just because an outlet is wired wrong. Do you think the venue owner will admit it was HIM who miswired the receptacle that killed someone? Some parts of the country are not regulated as well as others and I know of NOBODY in my Minneapolis local who would do this.

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  • Rob's Radio-Active
    replied
    Originally posted by TomCarlos View Post
    If you are using a cheap voltmeter for these kinds of ac tests, stop. Get yourself a "Wiggy." Wiggy is a brand. These meters are known as "solenoid" volt meters and there are many other brands out there. Solenoid meters require ample current in order to register a voltage. This helps cut down on inaccurate readings that low end VOMs can give.
    Plus, for those who are not experienced with operating/reading a meter with a multi-function dial, these are close to fool proof. I was a licensed master electrician for years working in industrial environments, and I still carried a Wiggy. They (most of the Wiggy types) also draw enough current to trip a functioning GFCI when connected between line (hot) and ground. This is not to imply it tests the GFCI's trip threshold properly, but it at least shows it is not completely stuck on.
    Rob

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  • guitician
    replied
    Just sell the guitars/amps with a non-contact voltage tester (NCVT). What passes for an electrician these days is bringing us back 50 years it seems.

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  • bsco
    replied
    Originally posted by olddawg View Post
    One of the reasons I always use a transmitter (other than walking into crowded or on tables) is that I NEVER trust an AC mains at any venue and almost never have time to check it. You could have a brand new modern outlet wired backwards with no earth ground. Happens all the time. Especially in remodels.
    I always use a wireless system with my guitar....have done so for years.....I would never part with it.......convenience and safety.....I had purchased a set of lamps from Wal-Mart a few years back.....two end table touch lamps, a small night table lamp and a taller pole lamp as a set.....When I plugged them in, every time I went to turn on the tall pole type lamp the breaker would pop....when connected by itself it worked fine....after checking everything out, this lamp was wired wrong right from the factory...I had to take it apart and reverse the wiring connected to the lamp socket.....goes to show..you can't trust anything...

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  • PeanutNore
    replied
    A GFCI extension cord or outlet adapter like this might be a good idea if you aren't sure if you can trust the outlet you are using. If current starts flowing where it isn't supposed to it cuts off the circuit within 1/30th of a second.

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  • Mick Bailey
    replied
    Testers also came up here;

    Grave electrical accident happened yesterday, May 25 2014

    CE marking means that the item complies with all of the EU rules that apply to it, so in the case of a guitar it could apply to the paint finish and material construction, as well as any electrical requirements. It reminds me of the British Standards - some items were tested and certified to the standards, but others were simply labelled 'Meets or exceeds British Standards', which could mean nothing. CE is just like that - meaningless unless the equipment has been independently tested.

    The cap/resistor ground connection for guitars works very well. It's also a good fix for noisy electro-acoustics with humming transducers; use a brass shim plate stuck under the bridge to contact the strings and ground it using the cap/resistor combo.

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  • pdf64
    replied
    With regard to the 'reverse bootleg' condition mentioned in the EC&M link in post #1, my 'Socket&See SOK32' socket tester identifies a 'swapped live / earth' error (I checked!) SOK32 - SOCKET & SEE - SOCKET TESTER + F/FINDER | Farnell element14

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  • R.G.
    replied
    Interesting question.

    The CE mark is necessary for sale of electrical-ish stuff in the EU. I have some minimal understanding of CE marking requirements, so this is going to be fuzzy. As I understand it, the mark does not mean that an independent testing lab has passed it, only that the maker has certified it to pass if tested. There may have been independent testing, maybe not. If an item is suspected of not passing, one of the independent testing labs can decide to test a piece of equipment on their own and see if they think it passes or not, and cause various degrees of regulatory trouble for the maker if they find it does not, including possibly recovering fees from the maker.

    In the case of Fender guitars, it makes it simpler to sell in the EU if there is no question about them representing it as passing standards. Since makers may self-certify the mark, they may have looked at their guitars, noted that there are no hazardous voltages in it anywhere, of any kind, and no potentials for shock or thermal danger, and decided "Well, sure it passes!"

    Or someone may have sniped them about having a product with wires in it and not having a CE mark.

    Hard to say. I am doing pure speculation, obviously.

    Edit: I forgot to mention. Having a CE mark does not limit your liability. CE marking is a change from government labs certifying and thereby conferring immunity on damage claims to the US model, where it doesn't matter who said it was safe, the maker is still liable in court if someone gets hurt. As I (dimly) understand it.

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  • loudthud
    replied
    Originally posted by R.G. View Post
    Hmmm. Fourthly (he pontificated...) the electric guitar is not an electrically powered appliance. For the purposes of electrical safety, it could be considered a wire which is connected to the amplifier's accessible metal and held in the hand. In and of itself, it has no requirements whatsoever for electrical safety review, and I bet the guitar makers would fight tooth and nail to keep it from being subject to review.
    Current production Fender guitars have the CE mark. Are they just limiting thier liability?

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  • big_teee
    replied
    That is one of the selling features of EMG Active pickups.
    You take the bridge ground off!

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  • Jazz P Bass
    replied
    Electrocuted On Stage:https://www.google.com/search?hl=en&...64.gJ2QtMJEzuo

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  • 52 Bill
    replied
    I seem to recall that back in the late '60s Dan Armstrong was recommending the use of a 0.1uF cap to connect the strings to ground.

    I'd guess that one of the many problems is that there are so many grounded metal parts on the typical electric guitar that you're bound to get zapped somehow.

    Leave a comment:


  • R.G.
    replied
    I don't know, exactly, but like always I have an opinion.

    First, it adds complexity, and I'm sure that in some cases, it would let some hum sources through. Solidly grounded beats capacitor- or resistor-grounded every time. And that's the way it has always been done, so guitar makers have no incentive to do it.

    Second, in the mostly-standard safety standards for the world, there is a lot of commentary about all user-accessible metal, for which guitar strings qualify, being grounded solidly enough to conduct 25A at the local mains frequency, which this thing clearly will not do.

    And probably thirdly, the issue only arises when the guitarist makes himself a bridge between two pieces of equipment, each of which independently might be judged to be compliant with standards, and which rely on a third part (that is, the building and its wiring) to make the accessible metals on both pieces of equipment be safe.

    We had a saying back at Three Initial Corporation: if there are more than two signatures on the document, the blame will never be placed. I'm guessing that might be behind the issue too.

    Hmmm. Fourthly (he pontificated...) the electric guitar is not an electrically powered appliance. For the purposes of electrical safety, it could be considered a wire which is connected to the amplifier's accessible metal and held in the hand. In and of itself, it has no requirements whatsoever for electrical safety review, and I bet the guitar makers would fight tooth and nail to keep it from being subject to review.

    Leave a comment:


  • Jazz P Bass
    replied
    Originally posted by R.G. View Post
    It's worth noting that the bridge (and hence the strings) of most guitars are solidly connected to the signal ground with a wire. There is a mod I saw once that put a 220K resistor in parallel with a 0.01/1kV cap in series with the bridge grounding wire. The 220K keeps the strings at DC ground, but won't let lethal amounts of 50/60 Hz in, and the cap "shorts" the strings for RF frequencies and keeps RF buzz down.
    As safe as this 'mod' appears, why is it not a standard.
    You would think the regulators would be all over this one like flies on p**p.

    Leave a comment:

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