Shocks to the lips from the mic

I also think it very important that we make it clear that breaking the connecting in the ground/earth AUDIO cable can be positive in terms of hum reduction when there are issues, but if anyone ever hears musicians (singling them out because it's stupidly still common practice) talking about removing the ground earth wire from 3 conductor mains plugs as a solution, it's your duty to tell them to not be so heart stompingly stupid!

Exactly

Alan.
 
Can you just run a new separate earth/ground around your studio and connect it onto the outer casings of your equipment. Got me paranoid now as I also use UPS devices for my pc equipment which is basically a battery pack to allow constant steady voltage protection from power cuts and surges. So no loss of data. But I remember transferring video on to pc from an old video player and getting a smack from one of the leads/adapters which converted and plugged into usb connection.
 
What you're describing in the UK used to be described as a technical earth. The idea being that in a studio complex, every piece of kit had access to a real effective hum removing ground, but then double insulated equipment not designed for needing grounding would get grounded, and then everyone started getting really angry about the 'pin 1' problem. Is xlr pin 1 supposed to be connected to the case ground? The feeling being that in some kit, this connection was a bad thing and often unpredictable in its impact on another bit of kit in the rack that absolutely needed isolation.

Electricity is viewed as simple, electricians viewed as skilled people a in practice nothing can be further from truth. I have just lost two lighting desks and two computers because of a wiring fault. The actual fault was 200m away and was a loose neutral connection, but revealed that one set of outlets in a control room were on a different phase to the others, and when the faulty connection arced, the voltage in the control room flared up to over 400, and the UPS did nothing happily passing it through frying the things connected through it. We need to put safety first, and in my example, it worked as nobody got a shock. Tingle reductions from leakage current are secondary, and hum reduction probably third on the list.
 
What you are talking about here is the problems you get when 3 phase power is used within a studio or live concert situation. Say for example the stage power is on 1 phase and the PA power is on a different phase, there can be residual volts between the phases of just a few volts due to unbalanced 3 phase loads. The unbalance may not be caused by the stage and PA themselves but say one phase in the building has a single phase electric motor running or loads of refrigerators and the other phase does not. I always try to keep the PA and stage on the same phase if loading allows, if not I try to have the front of house console and the stage power on the same phase. I tried to explain this out of balance phases in a Sound on Sound forum once and the replay from the so called magazine expert was very rude, say what you want but I have in fact measured the cross phase volts at 20 volts, hence the mouth shock.

In the studio I have 3 phase power, but I have air-con on 1, power on 2 and the lighting and kitchen on 3. Keep the recording gear on the same phase. The hums are caused buy the earths on the equipment and between the power points being different lengths.

Alan
 
Indeed - one advantage of cat5 interconnects seems to be the isolation and the old induced hums, buzzes and interference seems better. ironically, we have an old multicore with a mains cable strapped to it which has been a good solution for years and we used that to provide isolated clean power to the the lighting and sound kit. We never knew that for 25 years we had two phases there, and there was no labelling or indications of the possible issues. Just somebody taking some feeds and c connecting them in the intake room with no thought for the destination. Two sockets - next to each other on different phases feeding random kit in a rack. I know we don't have the old phase separation distance any longer, but 25 years ago we did! Dodgy earths, dodgy neutrals and 125Amp powering means a drifting neutral can have serious results. One computer had the power supply fried, but took the C drive with it. The lighting desks lost their power supplies too. An expensive day. We have a 6V difference between the earth on stage and the earth in the box at the back. Circulating currents make it easy to get hums. A few milliamps of tingle current is annoying but issues start around 20mA which isn't much, and 100mA across the heart can induce fibrillation and death. If 20mA can have an impact on some muscle function, it's dangerous. Acceptable leakage current is normally 3.5mA or less. 3.5 to 20 is not that much of a difference is it!
 
I am in Ireland and our earths/grounds are 4ft steel rods hammered all the way into the ground by each building with a thick earth wire connected to it from the fuse box. Anything with water (sink, radiator) has its own earth on top of the normal earth in the plug. It is no problem running another for safety. I get a slight hum from the dbx.
 
That could be an issue in England - multiple earthing being a tricky one to calculate. Steel would also be out - copper being the preferred material for mainly corrosion reasons. The use of lots of spikes minimises Zs between exposed metalwork, but is usually separate to RCD protection. The controversy is what happens when one electrode has a higher Ze and you try to measure it - what exactly are you measuring between - keeps electrical engineers happy. Luckily, I'm not one!
 
is the amp plugged into the same outlet as the mixer? If not then do so.
Sometimes that alone can fix the problem.
 
That could be an issue in England - multiple earthing being a tricky one to calculate. Steel would also be out - copper being the preferred material for mainly corrosion reasons. The use of lots of spikes minimises Zs between exposed metalwork, but is usually separate to RCD protection. The controversy is what happens when one electrode has a higher Ze and you try to measure it - what exactly are you measuring between - keeps electrical engineers happy. Luckily, I'm not one!

In the course of 29 years with an electric utility (National Grid, do you know of them? :)) I did my good share of testing grounding effectiveness of a substations grounding system to ensure fault protection equipment could properly detect and clear a ground fault. Sometimes the results of testing indicated more ground rods being driven and tied into the copper cable grid buried in the substation yard.
Residential grounding could be tested the same way.

We used a 'fall of potential' method and the far test rod might driven be about 3 kM out from the substation. Good day of hiking and exercise.
How To Do Electrical Grounding System Testing - E&S Grounding

Sometimes wallwarts can capacitively couple AC through them and if the gear they're connected to isn't grounded through some other gear can lend itself to shocks and noise problems.
 
In the US, cold water pipes are often used to attach the green earth ground wire to achieve earth ground potential. It's also possible to use a copper rod driven into the ground to do the same thing. Copper rods are usually the means of grounding lightening rods on buildings, too.

Seeing this is a UK system and because I'm very unfamiliar with your wiring system, I'll just sit back and read the posts. I do know a tingle or shock to the lips from a microphone can be scary, especially if you are also holding a guitar. At least the keys on a keyboard don't conduct electrical current.
 
Yes - totally crazy systems that makes so many systems buzzz like mad.

I also think it very important that we make it clear that breaking the connecting in the ground/earth AUDIO cable can be positive in terms of hum reduction when there are issues, but if anyone ever hears musicians (singling them out because it's stupidly still common practice) talking about removing the ground earth wire from 3 conductor mains plugs as a solution, it's your duty to tell them to not be so heart stompingly stupid!
please ...... I see this warning all the time as if you're doomed to die if you do that.
back in the day (60's and into the 70's) many amps just didn't have grounds at all and we got shocked so often that it was common practice to touch the git strings to the mic stand and look for sparks or listen for static.
Absolutely no one died.

I did a search for people who died that way and found exactly two documented cases and that's out of literally trillions of instances of musicians playing thru ungrounded amps.
Your chance of dying by bedroom furniture falling on you is much much greater.

And before someone pops in with the usual ridiculous comments, I am NOT saying everyone should remove the grounds.
i'm simply saying the warnings of death are WAY overblown
 
Well Bob, here in the UK we have a system of testing. Many venues, local authorities, organisations and groups spend thousands of pounds each year on testing EVERY piece of electrical kit and every piece of connecting cable. Some people use outside testing companies, some do a course and buy a tester.

In the past three years, since I've been testing I've had 27 fails. Just 3 of those involved missing grounds - out of probably 200 tests. None killed me. That, however, is not the point.

Removing a safety ground is stupid, and an accident waiting to happen. In my life I think I have had maybe 3 or 4 serious shocks from our 240V mains. I consider even 1 to be 1 too many.

If we promote removing the ground on a guitar amp, that gets thrown in and out of the truck, at some point, somebody gets a shock. Probably a fleeting glance that hurts, and they say ow! and get the thing fixed.

Statistically you are correct, but giving sound advice on safety is never pointless. Have I ever done it because the showtime was fast approaching and the guitar amp was humming away? Yes, I have - but doing it was irresponsible, and when you are standing up in court, knowing the death was a one in a trillion chance, it doesn't actually help, does it.

We are faced with a choice. Promote it as a cure, or promote it as bad practice. I choose to promote it as often as I can as a bad move. Having no opinion is not an option. Statistically the number of people killed on railway crossings is tiny - yet we spend money warning people not to do it, and this too makes good sense.
 
Bob, many venues now want to see testing tags on gear, the test is for earth continuity and wire insulation being up to scratch. Why would anyone bother putting earths on gear if we followed your logic? We recently had a young girl brain damaged for life, most likely because the MEN link (main earth neutral link) was not correctly installed in the main switchboard causing 240 volts to ground at an outside water tap. Don't mess with mains earths and make sure that the mains earth in you're building is wired correctly.

Alan

Just to clarify, the young girl was not a relative, when I said we I mean in our city.
 
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Frankly, this is the only moral, ethical and legal thing to do. Sure, smoking that last cigarette isn't going to kill you, but the message is important. Especially with forums. That bloke in home recording said it was OK to lift the earth in the connector, and I won't die ...................... Thump. Cue ambulance, police and a queue of legal experts.
 
Witzendoz alluded to what I am going to suggest. Do you have all of your equipment connected to the same wall socket or various sockets, because if different sockets (even in a house) the sockets could be wired back at the meter box to different circuits and the distance between these various connections could cause a small resistance between the earths and as a result could cause a small voltage potential difference and thus the small shock being experienced.

I know that at one major entertainment building (very famous !!!) that I was involved with for it first 16 years, all audio related equipment was connected to power points that were the same colour and all had one earth cable running between every power point (Technical earthed GPO). Even the GPO outlets on and around the various stages were the same and God help anyone who might have plugged a non audio related piece of equipment into one of these sockets. The earth wire being taken back to its own dedicated main earth point.

It was also the rule that any piece of equipment that was privately owned or hired in, had to be electrically tested and/or checked before it could be used, especially if it was going to be connected to one of the technical earthed GPO points.

Witzendoz, haven't heard much on the eastern side for quite some time re the girl. Did the Housing Commission ultimately accept blame and have they determined exactly who and/or what caused the problem and are they checking other similar properties for the same possible fault? Someone/s should really go for a row over this -- an innocent girl's life ruined forever and will quite possibly be greatly reduced in length.

My gripe for the day !!!!!!!!!

David
 
The Girl is Denishar Woods, she will never recover from this which is very sad. Due to it being a State housing house (government for overseas readers) there is a responsibility by the government to help them in the situation. However it has not been reviled who is responsible for the actual faulty work. Apparently the report has been finished (August) but has not yet been released. I should get the report when released as I am subscribed to the Energy Safety Bulletin due to holding a Gas Fitting Authorisation and being a project Manager for an Electrical Company (my day Gig).

Latest update here: Link

Alan
 
I would like to add my voice to those saying equipment earths should never be removed, that advice must stand in a public forum. Similarly I will not give out general advice regarding biasing amplifiers.

The "One in a trillion" concept is flawed, there is not that many people on the planet and certainly not that many amps!

On another tack? Brief mention was made os "DI" boxes? These are often touted as some form of safety isolation device? (but not by any of the mnfctrs AFAIK?) They are not.

The transformer might well have been flash tested to 1kV + but then the ground lift switch is often just an "audio grade" slide switch and NOT rated at 250V. Ground lifts also often have an RF tied down capacitor and that is not likely mains rated either. In any event, the fact that you CAN connect the ground rules out any safety property.

I guess you can get away with certain things with 115V mains and tool traffs used the generally survivable 55V above earth but with 240V ref ground? No chance!

Dave.
 
In the US, if you have any 2 prong plugs, and they don't have one larger than the other, to designate hot and neutral, they are pretty old school and mostly assume your house ground is correct. I remember, in the old days, if you had a buzz in the signal, you could just reverse those plugs, and many times, that would take care of it.

In today's world, plugs are either three prong with earth ground or one is wider, so you can only plug it in one way. There is no reversing the plug to get rid of any buzz. I'd be sure the house wiring is correct, so you can cancel that out. Also, I also like everything to be on the same breaker. Convert this post to UK talk.
 
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