Magnetic Field Trouble

Danger

****!
Don't worry too much, dude... we're here for you.

NoTime

I noticed that you said problems increased as you improved grounding.
A thought occurs to me.
The normal eletrical ground is made locally to the building.
However, everything is also grounded back at the various source points, Phone and power for example.

If you have a nearby transmision tower it also has a local ground connection.
Not all soils make for good ground points.
If a nearby tower had a leaking(arcing) insulator the power could possibly flow back into your ground connections to better grounds elsewhere.

business man

I will suggest it.

I talked to the dwp guy today that had a meter on the water pipes at the outside of building. He faxed over the graph and told me that everything was at or well below acceptable levels.

I am going to the building in the morning with my hvac guy to check out some wiring. He said today that one of our units showed 15 volts on the ground leg!!

He is not a wiring expert but he does have alot of hvac experience and he thinks it's a wiring problem. Four of our a/c units on the roof are, for some reason single phase, all others are 3phase.

I have a funny feeling he is on to something. The breakers for these units may NOT have been turned off the night we ruled out hvac as a possible problem. The breakers for these units were not marked, which he found out after tracing them today.

The problem I have with this direction is that why would the problems be so inconsistant and escalating and so random.

What do you guys think? It sort of makes me think we should have followed through methodically with more discipline the early suggestion of starting with everything off and adding things one at a time. The problem with this is we can sometimes go nearly all day without a single event and then have 5 in a matter of a few hours.

business man

The division of DWP that handles the DC line says that 2 of our events coincide with some sort of ramping up or down with their line, but two other events happened during a time that the lines were down for maintainance.

So not much help here so far.

Adder_Noir

Hmm...I'm must admit the fact you got two incidents whilst those lines were down does comply a bit more with conventional thinking that it's a wiring fault. I assume HVAC systems use quite alot of power.

A dodgy wiring fault would account for your problems. Remember that more than likely your HVAC will operate when sensors installed in your building tell it to. It will also shut off when your sensors tell it to.

Try increasing the level of ambient temperature you want the HVAC to achieve and see if this increases the number of incidents you keep having. Alternatively just get a HVAC engineer out to look at at. It sounds to me like you might have a hefty earth fault on one of your units which caues problems when the sensor kicks in and tells it to start up.

Danger

I notice that Russ hasn't been involved in this thread. He's the HVAC specialist; perhaps he's encountered a similar situation in his work.

Darryl

if i were ask to fix a problem like this, i would first determine if possilble, the source of your problem, is its
1. directly from the supply, ie, spikes or dips in the electricity from the power company.

2. is its inducted noice, or power from the near field magnegitc field.

3. is it voltage induced from the electric field.

you can measure magnetic field, with a compass, but you will not pick up transients, like spikes. or you may not pick it up at all.

if you buy a cheap test meter (multimeter) from radio shack, put it on the AC setting, you will read a voltage this is the Electric field indusing a voltage in the test meters leads.

take the meter home, and to work and compare the reading,

shielding and faraday cages will reduce electric and magnetic (electromegnet radiation) interference (induced voltage, current).

i would also try to see if there is any pattern to your outages, do they occur at regular times, ?

you can also purchase equipment that will clean up your supplied power, called "Power Line Filters". these consist of some capacitors and inductors, and are basically a 60hz filter for your power.

you can also purchase, a 1:1 power transformer, you put 115Volts AC in, and you get 115Vac out, but its isolated from the mains supply, and with the large amount of inductance of the transformer its acts like a filter.

yes, you can get harmonics on your power, when there is a spike or dip in your power, its is no longer a pure sine wave, but becomes are square, (with distortion), and harmonics are created,

you should also run power line filters in every peice of equipment as well, they are cheap and are often built into power boards.

Darryl

if your T1 line runes the length of the building, its a long antenna and will pick up induced ac from high power lines. and high tension,

is it possible to relocate your server to there your T1 line enteres your building, ??
and put your PABX system at the same location,

can you replace your wired phone and computer network with 802.11g wireless hub, and network. run laptops. and solve your power outage problems that way.. ??

Darryl

sorry for the multiple posts, its because i type before i think..

but i was trying to think of way to determine if you are in a strong electromagnetic field. one way is to use a NEON light, they require a high voltage to start but very very low current,

but those novality things you get for your cell phone, that light up when your phone rings, are the same thing, they are neon, that light up in the presence of strong electromagnetic fields.
i have not played with one of them, but i assume if you held one close to a power cable carrying current it would light up as well.

put one on your desk as see if it lights when your lights go out, or phone/computer.

business man

I was at the building for most of yesterday. I am afraid that there is more going on with the wiring than I thought. I personally helped to track down three problems that we still do not fully understand, but seem to be related to what we think was done by a very bad electrician who tapped legs of wires just because they showed voltage.

One case shows a small window air conditioner in a back wharehouse office being wired with some flourescent lights.

Another case where track lighting in the office shows a 5amp ground loop and some of these office lights are tied to a relay so that all office lights could be shut off at night by a single time clock. There were outlets and who knows what else added to these circuits conrolled by two relays that are powered through a breaker that in turn controls another circuit. These office circuits were known to be at their limit when staff, during the winter months tried to add very small space heaters under the desks and ciurcuits would trip so they had to stop using them.

There are other problems but these were the worst.

I will be very happy if this ends up being our problem but at the same time dissapointed that these problems were not given greater attention and addressed sooner. I am cautiously optimistic because there were events during the middle of the night when no hvac would be cycling and little or no load on any circuit yet breakers had tripped. Could everything in the building be so unstable that normally acceptable levels of emf's would put things over the edge?

We have evidence of fields from very sophisticated equipment and we know those fields fluctuate in intensity and diminish as you move further from the DC line.

Our expert knew we had ground loops based on the evidence from the meters all along but nothing was done about it because we were too busy getting phones and computers isolated from the problems, he was too busy trying to prove out the EMF theory, and I don't think he thought that this ground problem would trip breakers, especially with no load!

This may prove to have been an error in judgement and I should probably have been advised by my expert to bring in more resources/ electricians to address these wiring problems diligently.

The saga continues...

Paulanddiw

What about an oscilloscope? You could leave the probe open-circuit and see how much e-field there is and it's frequency. You could short the probe to ground with a length of wire e.g., 6" and see how much magnetic field there is.

Open circuit, you shouldn't get more than 50mVAC. Short circuited it should less than 1 mVAC. (my experience)

Interference from the DC transmission line would have a frequency of 120 Hz as opposed to that from the AC service in your building which would have a frequency of 60 Hz.

Darryl

yes,, your right a CRO, (cathode ray oscilloscpoe) would be able to tell you alot.

it does sound like you have a combinations of problems, each taking your systems to the edge of failure, or over.

poor earthing,
high indused Voltages from the power lines
strong magnetic fields at your location.
possibility of large spiks or dips on your local power system.
possiblity that the high power feeder is inducing power spikes into your local ac power grid ?

i dont know if you are using "earth leakage circuit breakers" on your appliances, do they trip ???

if your getting 5 amps "ground loop" current. is this leakage current, or is your electrician simply reading the current flowing in the earth side of your power system.

its your electricity power system 3 wire, (like here in australia), we have an
Active
Neutral
Earth

at the power box, there is usually a short circuit link between the earth and neutral. power to your appliance is supplied between Active and Neutral, with the earth as a safety,

this means current flows between active and neutral, if any current flows into the earth, its a fault and the earth leakage breaker will trip.

IF your neutral or earth line has measuragel AC voltage on it, this means your earth is not effective, and will also mean your equipment will be at an AC voltage and not and zero volts.

this causes problems with you interfact equipment together over a dispance, (you get earth current loops flowing), this would (and often does) cause equipment to fail, shutdown, or possibly give small "shocks" if touched.

see if you can divide your businesses power distribution into separate supplies for sensitive equipment, and another supply for higher power, and swited equipment, like AC system, lighting etc.

then on the supply for your computers/phone etc, you can install power line filters, isolation transformers, or a stand alone UPS, or constantly online UPS, so your computers are always powered by the UPS, this will isolate your systems from the power circuits, as much as possible.

reduce long cable runs, if you run alot of fluro's you might need to consider some Power Factor correction capacitors in your system as well.

Power factor is when the current and voltage of the AC power are not in phase, due to running alot of inductive loads, (like fluro's). and can cause problems as well.

when trying to solve problems like this, its important (IMO) to sort out what are "effects" and what are "causes". you need to try to focus on and fix the "cuases" of the problem, and not the "effects". otherwise you never really cure the underlying problem.

hopefully you are getting a handle on it, these are certainly a complex issues to resolve,

Adder_Noir

You need an inspect and test done ASAP. I assumed the majority of the wiring in your premises was sound given you're a commercial property.

With this new evidence I'd say it is a wiring error. Most likely you're suffering from what we call 'backfeeds' in the UK. It's were two lives from seperate circuits are routed back through the same neutral. It causes one breaker to sustain the current of two or more circuits worth of current when everything gets turned on. Given the nature of alot of your equipment being something that can draw current automatically when needed due to its electronic nature, I'd say this is what's happening.

If he was a really bad electrician then he could have used an earth as a neutral which would throw GFI/RCD type breakers. It's even possible he could have routed a live into earth then back out of it again onto another circuit or whatever!!

I know how to perform an Inspect & Test and I can give you the details if you like which will enable you to establish correct/incorrect wiring and polarity in your installation if you so wish.

I assume then from this latest information that it's most likely the same circuits which are giving you trouble all the time?

Oh by the way, your phone wire shielding is connected to ground. I'm sure I don't have to tell you how much trouble it would cause your phone lines if someone had made an earth live by bad wiring which was then routing current through the shielding of your phone line!! Hmm..it's all starting to become a bit clearer now!!

business man

I don't have the energy to write much tonight. Just wanted to let you know I am reading and taking advice as may be appropriate.
Today we had a local university proffesor at the building and he was very perplexed and interested to say the least.
We showed him pictures of the breakers on several panels that randomly tripped and switched to off position at 2:45 A.M. last saturday, which was our latest big event. He thinks it is a field problem but has never seen or heard of anything like it. He may want to turn it over to his graduate students.
Here is another question , if a breaker panel is closed and grounded, how could a magnetic field trip a breaker? The panel must act as a faraday cage right?
There are so many confusing things happening on the various recorded meter readings that I can't remember or understand it all. but the professor was shocked when he saw them.

Danger

This building wasn't constructed on an aboriginal burial ground, was it?

Darryl

burial ground sounds about right.

but i wouls say NO, ive never seen or heard of a breaker tripping by an external magnetic field, whether its inside or outside a metal box.

it might be possible, but i think the magnetic fields from a breaker right next to it would create just as strong an external field.

i think it IS possible the a Electromagnetic field could make high currents flow in a curcuit, and then the breaker trips from overcurrent, its normal mode of tripping.

Adder_Noir

To be honest before you go getting anyone else involved I'd just get a plain old spark (electrician) to come and test out your installation for faulty wiring.

I'll give you an example of just how serious a problem it can cause when something goes wrong with wiring. It concerns the outside lights on our house.

A few years ago we had an extension built by someone we know well. The building work was top notch but the sparks were as bad as anything you can imagine. Recently I pulled out all their garbage and it took me three days to figure out how they'd wired a small four light circuit which was sensor activated and also manually controlled by a switch. This is our home I'm talking about, not a huge industrial premises and the circuit is still a relatively simple one on paper too.

Anyway I removed all their wiring except the parts than ran behind plastered walls which were unreachable. I wired the outside lights off the supply they'd brought in from the board. It ran off the breaker which had 'lights' printed above it in red letters as opposed to the other one which had green letters above it.

Before too long after finishing the install the breaker starts going. This went on for several days. Then I discovered that the 6A red lettered breaker was controlling all the downstairs lights on the house, outside ones included. Its load was now well over 6A and closer to about 8A because the new outside lights are 300W each but also have the utility lights on them which makes for a total current draw of 6A off them alone.

So I thought, the breaker is going. But it's going intermittently? Ah!, thinks me, I know the reason - when not under fault current conditions most breakers and fuses will go a long time on overcurrent before they'll trip. A 6A breaker carrying 8A won't trip straight away. It will take a while.

So I kill off the original supply for the outside lights and run them off a fused radial circuit from the garage socket ring. It's on a 16A breaker with 2.5mm cable. No problem. Or is it?

Next thing I know I'm sitting on my dad's computer just like I am now and it goes:

*POOOOFFF*

Hmm...Clearly still not resolved. But now it's not throwing the red lettered light breaker, it's knocking out EVERYTHING in the house! But with the exception of the upstairs and downstairs lights???

Reason was...given that it was running off the garage socket ring it was now being protected by the RCD or GFI as in the UK it's common practice to have all your socket outlets extra protected by an RCD (or GFI in USA terms) which prevents earth faults. So at least I now know it's an earth fault that's doing it. I scratch my head and bingo! A quick look outside reveals the problem.

One of the original power legs coming out above the utility room window which I'd terminated in the box was still connected to a small stub on the other side of the box which was exposed to the rain. And that's what was causing it all.

Are you beginning to see just how big a problem you might have if your building has been wired badly and electronic devices which can turn themselves on are requesting current every now and then? I agree it may not be the entire problem. In fact even if it isn't the problem at all, then you must get it ruled out before you can continue any further or you'll go crazy (trust me).

LOL if you'd pay for the flight and a suitable test meter I'll come over and have a look myself