That little A/C receptacle tester....

[xnewyorka]

It's actually pretty scary that somebody thought this was a good idea...

Well, what is the alternative? Refuse to play until they fix it? Depending on your stature, that may or may not go over too well. If you are a hundred percent positive you have diagnosed the issue correctly, it seems safe enough, as long as you communicate effectively with the person in charge of the power and make sure that they don't touch a thing. Of course then again, if something goes wrong, it's all on you.

Guessing you might not approve of my 10 ft extension cord with a male plug on both ends that connects my generator to my outside outlet when the power is out. ;-)

 

[SactoBass]

This is a link to the tester.

https://www.amazon.com/Electrical-Receptacle-Outlet-Ground-Tester/dp/B0012DHVQ0

Get one and use it EVERY time you go to a new venue.

Chuck: *THANK YOU* for posting this for your fellow TB'ers! This is an excellent example of bassists helping bassists!

 

[agedhorse]

Guessing you might not approve of my 10 ft extension cord with a male plug on both ends that connects my generator to my outside outlet when the power is out. ;-)

No sir, I do not. I have some good friends who are linesmen, and what you may not be aware of is that one of the most dangerous things a linesman can encounter while troubleshooting is a generator back-feeding a premises. All it takes is an accidental (or simply stupid) mistake such as forgetting to open the feed breaker, or somebody else closing it without your knowledge to energize a distribution line to its rated voltage by back-feeding the distribution transformer. Even though there are utility service precautions taken to reduce the risk to personnel, nothing is 100% effective.

FYI, there are plenty of jurisdictions where you can be held criminally liable (not just civil liability) for damages, injury or death that is caused by doing this, and I think it's good to hold a fool accountable for damage caused by his actions.

 

[xnewyorka]

No sir, I do not.

Nice double-stop -- dually noted!
Only used it once, when we had a newborn and couldn't be without heat.
Don't worry, a proper setup is on the project list!
To show my respect for your eloquent post, I'll go cut off the plugs now and wire up the cable for use with an extension cabinet! It's a nice fluorescent green 12 AWG cable, so I'll never lose it on a dark stage.

 

[agedhorse]

Just install a proper transfer switch, they are not very expensive.

 

[Al Kraft]

Just install a proper transfer switch, they are not very expensive.

....one of the cheapest and easiest ways to do an incredibly smart thing that I know of.

 

[Pops OB]

Played a live radio show last night. The event is a volunteer event where gifts for underprivileged folks are wrapped. I have played it for many years and this year we were in a new venue....and that is where the trouble starts.

I arrived and the sound man for the radio station asked what I needed to get hooked up. I told him I just needed power and that he could plug in to the D.I. on my Aguilar AG 700. So he brings me power from an extension cord and I power up my amp and it is working fine until he plugs into the D.I.! Sparks...smoke..and a blown AG 700 and a blown Mackie Mixer (the radio station's mixer). Great.

I went to my car and retrieved my back up head..Genz Benz Shuttle 9.2. Plug it in but then thought about that little receptacle tester in my bag...plugged in the tester and it showed the power was wired wrong!

Got extension cords and ran power from a correctly wired receptacle and thought all was right. My amp powered up fine and sounded good. Then the sound guy went to plug in to the D.I. and again I see sparks fly! The Shuttle was still working but I had fears about the D.I. being damaged. Played the gig and came home and checked the Shuttle and, sure enough, the D.I. is damaged.

The radio station is going to pay for the repairs but, man, I sure wish I had used that little receptacle tester before I turned on my Aguilar.

This is a link to the tester.

https://www.amazon.com/Electrical-Receptacle-Outlet-Ground-Tester/dp/B0012DHVQ0

Get one and use it EVERY time you go to a new venue.

You can also get this exact one at just about every hardware store and Home Depot. I ALWAYS carry one in my tool bag that goes to every gig with me.

 

[Spidey2112]

Good stuff. I guess my question would be : You get to the gig and test all the outlets on stage, and they are all wired incorrectly. What do you do ?

In legalise, insert a clause in the contract between you and client, stating all electrical will be up to code, by show time... or, no show, but you still get paid for doing your part, in showing up...

... worth a try. $75-150 for the average gig isn't going to cover damage to your equipment, let alone the possibility of injury to yourself, and/or others.

 

[Ewo]

Was doing a little more reading about bootleg grounds, and found a discussion thread started by Mike Sokol, the who wrote the article on reverse polarity bootleg grounds linked above.

Reverse Polarity Bootleg Ground Testing

Some of the same material in his article, some additional info.

 

[AddBass]

You can also get this exact one at just about every hardware store and Home Depot. I ALWAYS carry one in my tool bag that goes to every gig with me.

I tried the type with the GFI tester button, but found it real easy to hit the button accidentally so ended up getting one without. I didn't want to risk tripping an outlet and having to search for it.

 

[Wild_Bill_57]

90% of the venues we run into have some sort of jack leg, half a-- wiring going on. This goes for bars, festivals, even event venues. We have just gone to providing 99.9% of our own power and distribution for every event. No more grounding issues, reversed polarity, tripped breakers, or noise issues. Now I do have the advantage of owning a production company. We run off of our own whisper quiet gen sets right on the trailer, everything is GFCI protected and earth grounded. Doesn't matter if it's a single 20a circuit or a 200a 120/208 feeder / Distro system. It's a little on the extreme side, but we never have an issue. Several times we have been told we are the only ones that never have a power problem. Even using our own motion labs Distro systems, I still meter every thing before anything is connected.

 

[johnson79]

Guessing you might not approve of my 10 ft extension cord with a male plug on both ends that connects my generator to my outside outlet when the power is out. ;-)

I sell electrical supplies for a living. There are plenty of cheap transfer devices for portable generators. The easiest is a male/female cord, male inlet, and transfer device. It's not worth the risk to yourself and others. Backfeeding onto the utility line can be deadly to a lineman that is repairing damaged cables or equipment.

Let me know if you need some help selecting the right equipment. Seriously, send me a PM if you want.

 

[beans-on-toast]

Low voltage is common in some dives. It can sag when everyone is plugged in. Lighting loads can make it worse. When the supply voltage is too low, it can damage your amp.

As mentioned previously, measuring the voltage, under load with all the gear powered up during soundcheck is a good idea. This is one safe way of measuring the line voltage. It can be plugged into a power strip.

https://www.amazon.com/Generic-Digital-Voltage-Voltmeter-100-300V/dp/B00MGMBCRK

Some amps have a built in line fault circuit. Below, a certain voltage, the amp will shut down. If it happens and you can note the voltage, at least you’ll know that it isn’t a problem with the amp.

 

[Hoochie Coochie Man]

Was doing a little more reading about bootleg grounds, and found a discussion thread started by Mike Sokol, the who wrote the article on reverse polarity bootleg grounds linked above.

Reverse Polarity Bootleg Ground Testing

Some of the same material in his article, some additional info.

Thanks for posting that link. More complete information than the one I posted earlier.

The owner of that forum, Mike Holt, has authored a number of text books targeted to training electrical apprentices. I have a few of his books, and they are excellent. They are well written, clear, concise, and comprehensive as they relate to installing electrical equipment properly. I highly recommend them. Mike Holt Enterprises - The Leader in Electrical Training.

Another good source of information for questions regarding how to interpret the National Electrical Code, is a publication called NFPA 70: NEC Handbook. Buy NFPA 70: National Electrical Code (NEC) Handbook

 

[Ewo]

Thanks for posting that link. More complete information than the one I posted earlier.

One tidbit that jumped out to me was using a non-contact voltage tester when I set up. Duh-uh. I have one of those to use around the house, but it never dawned on me to use it to check for potential on a mic case. Think I'll put it in my run bag to bring to gigs.

 

[Hoochie Coochie Man]

One tidbit that jumped out to me was using a non-contact voltage tester when I set up. Duh-uh. I have one of those to use around the house, but it never dawned on me to use it to check for potential on a mic case. Think I'll put it in my run bag to bring to gigs.

The effectiveness of your non-contact AC voltage detector for this purpose depends on the sensitivity of the particular tester you use. Some testers have a sensitivity adjustment. I suggest that you experiment with the tester to see how it responds to different circumstances. If the tester is too sensitive, it may indicate voltage where none is present. I like the Fluke testers. You have to insert the plastic tab on the end of the tester into the slot of an energized receptacle before it will indicate the presence of voltage. Some testers will indicate voltage when positioned near the face of a receptacle.

Edit: Any method used to detect no voltage present should be verified to actually detect voltage when it is present so the user is not misled by a faulty meter, or indicator. I have had meter leads, and leads on neon testers go open in use with no obvious visual indication of damage.

So, the first thing to do when trying to confirm a circuit is not energized, is to observe the tool to read voltage, or light up, or beep or vibrate, (or whatever it does) on an energized circuit, so you have more confidence that when it indicates no voltage it is because there actually is no voltage, (and not a broken wire, or dead battery in the tool).

 

[Ewo]

Thanks for the tip! Yeah, I happen to have a Fluke VoltAlert. With the tab stuck in an unused outlet, it shows voltage on the hot but nothing on the neutral, and nothing if I move it around on the faceplate.

So to check a mic, I'd turn it on and hold the tab on the case and windscreen, yeah? And I could use it the same way on the chassis of an amp, my bass strings, like that?

 

[Hoochie Coochie Man]

Yes

 

[cazclocker]

Was doing a little more reading about bootleg grounds, and found a discussion thread started by Mike Sokol, the who wrote the article on reverse polarity bootleg grounds linked above.

Reverse Polarity Bootleg Ground Testing

Some of the same material in his article, some additional info.

DAY-YUMMMM.... this thread has turned out to be filled with absolutely vital information. As working musicians, we routinely stroll into new venues which have electrical hookups with unknown integrity. Some of this stuff could potentially save some lives. Seems like this thread could be worthy of becoming a sticky..??

 

[Blues Bass 2]

This thread reminds me of a solution I used to carry with me to EVERY gig. I had two pieces of gear to deal with house wiring at any venue:

1. A wiring tester, like the OP recommended.
2. A homemade 4-outlet junction box. Two of the outlets were wired normally, just the way any up-to-code outlet should be wired. The other two outlets were deliberately wired with (1) the hot and neutral reversed and (2) the ground and neutral reversed.

So the first thing I’d do at a new venue was to check the house wall outlets with my tester. If the outlets showed the hot & neutral reversed, then I’d just plug in my junction box into the incorrectly-wired outlet. A quick recheck of the outlet that also had the hot & neutral reversed would show that the problem had been rectified... sometimes, two wrongs make a right! And if the original problem with the house wiring was the ground & neutral were reversed, my junction box had an outlet for that, too.

When I built the junction box, all the wiring was heavy 12-gauge, as I recall. And the cord was short.

I lost that junction box some years ago when it was stolen. I should build another one.

Please don't build another one . This is wrong on a lot of different levels . It is a safety violation and is against the National Electrical Code (NEC) that protects people from fires and electrocution . If someone was to get hurt from misusing this whoever built it would be liable for the damages . A ground should never be hooked up to a current carrying conductor like a hot or neutral except where it is bonded to the neutral at the service entrance of a building . This is the only time .

A ground basically connects to the metal parts in a device like your amp chassis or to any other metal enclosure that houses electrical circuits like your refrigerator , microwave and even the electrical panel . If any of the wiring in the device comes loose and touches the grounded metal the ground wire gives it a path back to the circuit breaker or fuse so the circuit will trip the breaker or blow the fuse . Swapping the ground with a neutral defeats this and is dangerous to equipment and people . The circuit breaker or fuse may not turn the circuit off if something goes wrong with the ground altered .

Don't mess with or alter the ground !

The best thing to do is just find an outlet somewhere that is wired the right way by using a tester like a bunch of people already said on this thread . Do what you have to do , use a long drop cord if you have to but NEVER use a miswired outlet . Let someone from the building know about it so they can have an electrician make it right but don't use it no matter what . Your life and your equipment are at risk if you do .

I'm a retired IBEW Journeyman electrician , Local #145 , and just want my bass playing brothers and sisters to be safe to make music and live a good life .