That little A/C receptacle tester....

[beans-on-toast]

And when you’ve located that good outlet way over yonder, it pays to carry a good quality, heavy duty, contractor grade extension cord. They are available at hardware stores.

Search Results for Contractor extension cord at The Home Depot

 

[Chuck M]

I was reluctant to begin this thread because I am very embarrassed that two of my amps were damaged. I did think a post might prevent others from making similar mistakes so I decided to post about my experience.

I am glad I did because I have learned a lot from many of your thoughtful posts. I thank you and will post when the amps are repaired. The Genz Benz will ship out today or tomorrow. Still waiting for an RA from Aguilar although I emailed them Tuesday night and called them Wednesday. Who would think it would take that long for an RA to be issued?

 

[BurningSkies]

This whole thread is a solid reminder of why you should check not only the AC supply at every venue, but also every signal cable for proper polarity/continuity.
This can be easily done with either a volt/ohmmeter (hell, they give them away free down at the Harbor Freight store) or a dedicated tester. There are several multi-function units on the market that test XLR and 1/4" cables, as well as phantom power voltages and buss fuse continuity by simply inserting one or both ends in the tester.
Your life ( and your gear) is worth spending a few dollars to protect.
Glad the OP wasn't injured, other than just financially.

Can anyone actually point to a cable tester that will serve this function when you are handed an XLR for your DI on stage? I mean we carry a basic cord tester for continuity. But something that will take one end of an XLR and tell you that it's seeing the legs switched, etc?

 

[Jim C]

Reversing the neutral and hot on a 120V cat) does not matter safety-wise (though it's a terrible practice)

Of course on 120/240V and 120/208V 3 phase wye it would be disasterous.

Don't most residential panels have ground and neutral tied together?

 

[HolmeBass]

That is a true gig horror story. The problem is what do you do if the wiring isn’t right and you don’t know how to fix it? Just bag the gig? When the venue says, “So and so played here last night, people play here all the time, why are you causing trouble?” What do say? What do you say to your bandmates who have never tested an outlet to in their life?

 

[BurningSkies]

That is a true gig horror story. The problem is what do you do if the wiring isn’t right and you don’t know how to fix it? Just bag the gig? When the venue says, “So and so played here last night, people play here all the time, why are you causing trouble?” What do say? What do you say to your bandmates who have never tested an outlet to in their life?

Part if the sitch is that many won't notice this situation because they either aren't touching a mic or using a DI.

 

[HolmeBass]

Part if the sitch is that many won't notice this situation because they either aren't touching a mic or using a DI.

I guess since I don’t sing I’d either carry the room with my rig or ask to be mic’ed.

 

[agedhorse]

Don't most residential panels have ground and neutral tied together?

Only at the service entrance, which is where all legally required bonding is done.

 

[Jim C]

Only at the service entrance, which is where all legally required bonding is done.

So, does UL require that a MI amp have a separate neutral that is not tied to the amp chassis ground?

The reason I ask:
I worked for a twin 24 track remote truck back in the day.
Standard master main residential panel with 2 legs of current and a neutral with an isolation transformer at the power entry. (transformer before panel)
We had a ground cable / ground rod set up but rarely used it.
Many times we were parked on the street or in a parking lot that would have required some demo and excavation for a low impedance ground. The assumption was that the rubber tires isolated the gear and staff from any shock hazards.

As I recall, the only time we were asked for a safety ground hook up was for a festival at the monument grounds in DC. which was easy since we were parked behind the stage on the grass.

 

[Hoochie Coochie Man]

Don't most residential panels have ground and neutral tied together?

In all residential services in the USA, the main bonding jumper connects the service neutral conductor, the grounding electrode conductor, the grounded circuit conductors, (neutrals), and the equipment grounding conductors, (grounds) at the service disconnect. That is the only place these conductors are permitted to be bonded, (connected), together.

The text I typed in bold above are the words used in NFPA 70 to define the different conductors in an electrical system. The reason these conductors have different names is that they all serve different purposes.

The grounded circuit conductors, (commonly called neutral), serve to return current back to the source, (via the service neutral conductor to the center tap of the transformer).

The equipment grounding conductors do not carry any current under normal conditions. They carry fault current back to the panel when something is wrong.

The grounding electrode conductor provides a low impedance path to the planet Earth ground the service sits on. It primarily serves to protect the system from damage due to lightning or excess voltage.

 

[Blues Bass 2]

Don't most residential panels have ground and neutral tied together?

The neutral and ground are bonded at one spot on the service , either in the meter socket or most commonly in the electrical panel . They are at the same potential there electrically . At the service the grounding wires that run to the ground rod and usually the cold water pipe in the building have enough current carrying ability to trip the breakers or fuses for any short circuits on any properly grounded circuit .

Neutrals carry current as well as the hot wires . Grounds need to be separate from current carrying conductors to do their job . Short circuits take the closest path to ground . So if someone tries to tie the neutral and ground together on one of the branch circuits , like in a receptacle , if something else on even a different circuit shorts out and that receptacle happens to be closer than the bond at the panel , the short circuit current may try to take that path .This also creates a ground loop . It may or may not be enough to trip the breaker . This is the main reason that all grounds should go back to one point .

The post above beat me to it .

 

[cazclocker]

That is a true gig horror story. The problem is what do you do if the wiring isn’t right and you don’t know how to fix it? Just bag the gig? When the venue says, “So and so played here last night, people play here all the time, why are you causing trouble?” What do say? What do you say to your bandmates who have never tested an outlet to in their life?

Perfectly valid question. I’d like to know the answer. Following this thread is quickly showing that electrical problems can quickly turn into a poop-storm.

 

[Hoochie Coochie Man]

Blues Bass 2. I may have posted before you, but I bow to your superior knowledge, experience, training, and certification as a licensed electrician, and member of the IBEW.

I am merely a person of great curiosity with a library card.

 

[agedhorse]

Note that the bonding of water & gas piping, CATV, Telco, building steel, buried reinforcing steel to the ground bond point it to help insure that these structures stay "reasonably" equipotential" in the event of an electrical ground fault, as well as in the case of a lightning strike. It's (primarily) the voltage DIFFERENCE between accessible elements that is the (electrocution) danger.

 

[agedhorse]

So, does UL require that a MI amp have a separate neutral that is not tied to the amp chassis ground?

The reason I ask:
I worked for a twin 24 track remote truck back in the day.
Standard master main residential panel with 2 legs of current and a neutral with an isolation transformer at the power entry. (transformer before panel)
We had a ground cable / ground rod set up but rarely used it.
Many times we were parked on the street or in a parking lot that would have required some demo and excavation for a low impedance ground. The assumption was that the rubber tires isolated the gear and staff from any shock hazards.

As I recall, the only time we were asked for a safety ground hook up was for a festival at the monument grounds in DC. which was easy since we were parked behind the stage on the grass.

You are asking 2 different but related questions that raises a good point about the use of isolation transformers in a stand alone application.

1. UL (all of the 60065 requirements, of which UL is one signatory) does not allow the bonding of either the neutral or hot conductor to the chassis ever, and there are tests that are performed on each unit to insure that this isolation from the chassis withstands very high voltages without breakdown. (HIPOT testing)

2. Whenever an isolation transformer is used, that brings about an entirely different set of codes. If the isolation transformer is actually UL listed as an isolation transformer, then I believe there is no requirement for re-deriving a ground after the transformer, but I do believe that the frame of the trailer, and the frame of the transformer must be bonded to the incoming power's grounding conductor. Generally, the isolation shield winding on the primary side is also bonded to the incoming power's ground. Now where it gets weird is what may be required on the secondary side, which is different from a standard unit transformer (that does not have listing). I haven't looked at this part of the code in many years, but I would think that there would still be the requirement that the trailer frame be bonded to earth (for equipotential reasons in the event of a primary fault), but there may also be a distance rule that may allow the primary's grounding conductor to suffice until the fault voltage rise (due to fault current) becomes dangerous.

 

[beans-on-toast]

All this talk of grounds has me wondering. I'm sitting on the 27th floor of an old building, there are an additional 9 below ground levels. They must have used some large diameter down cables to maintain equipotential grounds. Then there are complications such as maintaining grounds in the event of an earth quake. Large buildings tend to have their own sub-stations to tie it all together.

Makes you appreciate that there are people that do nothing but specialize in designing grounds and wiring for buildings.

 

[Drgonzonm]

That is a true gig horror story. The problem is what do you do if the wiring isn’t right and you don’t know how to fix it? Just bag the gig? When the venue says, “So and so played here last night, people play here all the time, why are you causing trouble?” What do say? What do you say to your bandmates who have never tested an outlet to in their life?

when you have a problem, say, look we are willing to pay for an electrician if we are wrong. As k for email or cell phone number send a text email to owner manager of facility to document conversation. I am a troublemaker so I might call the fire Marshall, or osha. (Use the name John Q public)
Make sure you have a photo of the test before you ask for assistance. If you walk away, use small claims court.
It's my experience, many people who have had problems might not complain or worse, you are being lied to.
Did I see, a post about having language in a contract that the place is safe to play?
The way I look at it, who pays the price, If equipment is fried, or someone is shocked?

 

[HolmeBass]

when you have a problem, say, look we are willing to pay for an electrician if we are wrong. As k for email or cell phone number send a text email to owner manager of facility to document conversation. I am a troublemaker so I might call the fire Marshall, or osha. (Use the name John Q public)
Make sure you have a photo of the test before you ask for assistance. If you walk away, use small claims court.
It's my experience, many people who have had problems might not complain or worse, you are being lied to.
Did I see, a post about having language in a contract that the place is safe to play?
The way I look at it, who pays the price, If equipment is fried, or someone is shocked?

I know one surefire way to botch booking a gig with a club around here is to ask for a contract. Ain't no one got time for that!

I am not sure exactly what the point is - "we are willing to pay for an electrician if we are wrong" - how does that work? They hire an electrician, he comes out, he either fixes it or doesn't, then they just say there was nothing wrong here's the bill? I am not going to say that. Besides what are we going to do, wait until the electrician has shown up to play? Just doesn't seem feasible to me. It's more of an issue of how to handle not taking the risk with the bad electricity and not breaking off the gig or pissing off my bandmates (by breaking off the gig).

I guess I would keep testing plugs until I found a good one and then insist on using it, and just hope it wasn't on the refrigerator's or exhaust fan's circuit.

I would mention it to the club's ownership/management for sure and let them know it is potentially a safety issue. If they didn't fix it by the next gig, I would start to lobby to not play at that place anymore. Calling the fire marshall or OSHA is not going to go over well, and since I pointed out the them the socket was bad, they'd pretty much know who ratted them out.

 

[Drgonzonm]

If it's only one recpt, put some baby covers on it, that is red tag It.

 

[tlc1976]

when you have a problem, say, look we are willing to pay for an electrician if we are wrong. As k for email or cell phone number send a text email to owner manager of facility to document conversation. I am a troublemaker so I might call the fire Marshall, or osha. (Use the name John Q public)
Make sure you have a photo of the test before you ask for assistance. If you walk away, use small claims court.
It's my experience, many people who have had problems might not complain or worse, you are being lied to.
Did I see, a post about having language in a contract that the place is safe to play?
The way I look at it, who pays the price, If equipment is fried, or someone is shocked?

I'd say be prepared to actually pay that electrician, and maybe lose the gig out of spite from the owner, who may be losing customers if you're not playing. If the gig is on an evening weekend (which is considered emergency hours), that's extra. Not an electrician but I called a plumber/heater once on a weekend and paid $175 for him to say "yup you got a leak" and it would be an additional $100 just to unlock the warehouse if I did want the part, part and install would be extra. It was 10 days after moving here, didn't have my tools here yet and gf was freaking out. I kept it shut down until I was able to fix it myself. And for the electrician to actually say anything is wrong, especially when everyone else says it's fine? Electrician may take the easy money to show up especially if offered free drinks. When I installed my new furnace and pipe, the inspector didn't even look at the pipe, or even turn on the furnace. Just stickered it and left. Same for one of my coworkers and his furnace. Same guy has been fighting for a year over a new fireplace that smokes up the house every time he uses it. Inspector signed off on it without even really looking at it, CO and smoke in the house is a health hazard but the contractor who installed it technically doesn't have to do anything because inspector signed off. For establishments it's often cheaper to pay OSHA the fine than do the work. Happens all the time. Especially small establishments couldn't afford to stay in business if everything was constantly to code. From what I've seen anyway, YMMV.

Providing your own power would be the answer but is not practical, or sometimes even possible. Maybe it's already been posted, but maybe there's a device that can take dirty power and isolate your equipment from problems like spikes, shorts, bad grounds? Or maybe if it does exist, it costs a king's ransom? I know the basics but am not an electrician so excuse my ignorance.