The owner was upset??

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charlie

Senior Member
Location
Indianapolis
Re: The owner was upset??

Why would they do that? I don't see anything wrong with this installation. I think the electric utility was just being hard to get along with and was pushing the customer around. :( :D :cool:
 

joe tedesco

Senior Member
Re: The owner was upset??

charlie:

I was also wondering the same thing! Who do they think they are those utility guys!

I think that the people just decided that they didn't want to use any of that darn old electricity anyway.

I just can't understand those people who are the makers of the power, and the grids and the transformers.

I wonder if anyone has any experiences with a very large transformer located between two buildings where the top of the transformer is about 2 feet away from the first floor apartment window. I have been told that the noise is hard to deal with when the window are opened.

Do you know of any rule that might apply that would not allow them there?
 

charlie

Senior Member
Location
Indianapolis
Re: The owner was upset??

Actually Joe, there are no rules that restrict the location of an electric utility transformer from any window, wall, door, etc. unless there are local rules established. IPL requires 10 feet to any combustible wall, window, door, overhang, etc. and 5 feet to a noncombustible wall. Other electric utilities have different rules. :cool:
 

karl riley

Senior Member
Re: The owner was upset??

If ever the current World Health Organization recognition of 4 mG AC magnetic field as a possible carcinogen for childhood leukemia trickles down to local electrical levels, this may provide the basis for the siting of transformers.

They have a very high field, but because they are coils, the field weakens rapidly, eventually by the cube of the distance, so you don't need a great deal of space to get to, say, 1 mG. But 2' outside the window puts a high field into the house, which some lawyers have argued is a trespass.

Seeing kids sitting on pad mounted Tformers makes me feel frustrated at the slow pace of knowledge dissemination. Particularly when it is slowed due to corporate financial motives.

Karl
 
G

Guest

Guest
Re: The owner was upset??

Karl,
What is the EMF danger range from an MRI magnet?

Additionally, is there any effective shielding short of distance?

Please don't consider this as an effort to go off-topic.

Also, I have a pocket pen-sized Inductive Voltage Detector model #1010. Does this detector indicate EMF? I have noticed that on some covered switches it will sense at a foot away, while other covered switches will cause no detection of voltage. An uncovered load wire might detect at 8" or 2". Some NM cabling that not even made up yet will detect voltage from 8" away yet my digital VOM will only detect .002 volts. The "projection" of electrical waves is very interesting. What are the hazards and/or effects at these low voltages (120 volts)?

Thank you for your helpful research regarding EMF's.

../Wayne C.
 

cm

Member
Location
Pennsylvania
Re: The owner was upset??

Harry home owner knows it all home depot and lowes taught them, Those of us that do it for a living we are just dumb installers :D

[ September 09, 2003, 05:06 PM: Message edited by: cm ]
 

big john

Senior Member
Location
Portland, ME
Re: The owner was upset??

Awwt,

When I got my non-contact voltage sensor (one of the Fluke models), I thought it was the best thing since sliced bread. I did some very basic experiments to see how it worked:
The sensor will activate a good distance away from the television screen when the TV is on.
However, put a piece of aluminum foil between the screen and the sensor, and it will stop activating.

Also, there is an extremely strong, if localized, magnetic feild present in the floor of Metro trains. Strong enough that it will hold one end of a paper-clip up in the air if you put it in the right spot on the floor. However, this does not activate the sensor.

This leads me to believe (and for those of you who are engineers, forgive me if I don't have this right) that it senses the electrical feild aspect of an EM field. It operates by being capacitively coupled to the circuit you want to test. You can shield things from electrical feilds (this is why the sensor won't work on BX) but it is much harder to sheild the magnetic fields (this is why paper clips dance on the trains).

I don't know what the WHO has discovered by I am suspect of anything regarding the detrimental affects of EMF: If one of the dangers of being an outside lineman was the fact that you'd get cancer in twenty years, you better believe IBEW would have instituted some sort of fund to help compensate the afflicted workers.

-John
 

karl riley

Senior Member
Re: The owner was upset??

Big John, you are right on about the voltage tester. It responds to electric fields, which are easily shielded. It tells you nothing about the magnetic field.

About health effects, the research shows more cases than can be accounted for by chance. It doesn't mean everyone will get it. A large Canadian utility study did show some disease connections to a combination of high electrtic and magnetic field exposure after many years.

Unions have shown no interest in the topic. Go figure.

Awwt: MRI's are DC. I have no info on any studies on DC health effects. AC induces currents, DC just lines up your electron orbits.(!)

Shielding of magnetic fields can be done actively (counter-current loop sets up counter-field) or passively with mu metal, heavy iron plates, and heavy aluminum plates that dissipate energy by allowing eddy currents to convert to heat). Lead does nothing (or earth or brick, etc).

For further info do a search on the net. You will find all the info you need.

Karl
 
G

Guest

Guest
Re: The owner was upset??

I did search the net, and I found you :eek:

../Wayne
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Re: The owner was upset??

Originally posted by big john:This leads me to believe (and for those of you who are engineers, forgive me if I don't have this right) that it senses the electrical feild aspect of an EM field. It operates by being capacitively coupled to the circuit you want to test.
I?ve never seen a non-contact voltage tester, and I never really got along with the whole field :roll: of electromagnetism. But speaking as an engineer, I can offer the following observations about physical laws:
(1) Any charge will set up around itself an electric field.
(2) Any other charge within its range will feel a force, either towards it (opposite charges) or away from it (like charges).
(3) Any charge in motion will set up around itself a magnetic field.
(4) Any other charge in motion (or any magnetic material) within its range will feel a force.
(5) Similar to (4), a stationary charge that finds itself in the presence of a moving (or changing, as in AC) magnetic field, will also feel a force. When the charge moves, it is called ?current.?

What I would ask is whether your non-contact voltage tester can detect the presence of voltage, when the device is turned off (i.e., no current). Can it detect voltage in a receptacle outlet that has nothing plugged into it? If so, then it is not detecting a magnetic field, since rule (3) requires the charges to be in motion (i.e., current). But a receptacle outlet that has power and that has nothing plugged into it will have an electric field, per rule (1). So if this correctly describes what the tester can do, then I must conclude that Big John is right about it using capacitive coupling to sense an electric field.
 
G

Guest

Guest
Re: The owner was upset??

Got it. Thanks. It uses capacitance to sense the electrical field. It will work in an outlet with nothing plugged into it. You don't even have to touch the outlet. As stated before it's technically called an "Inductive Voltage Detector". It puts on a pretty good show too-- it has an eerie red light and a peculiar buzzing sound not much different than certain species of Cicada's. It drives home the power of an electrical field, and it keeps you safe. You put it in your pocket and you never stick your fingers in an outlet box without first pointing your pocket detector near the outlet box.

It acts as a simple tick tracer too. You can trace wires in a wall with it. It's not too accurate or reliable for that purpose, but it can find an open circuit in the wall within reason, and it can detect the presence of live circuits within a wall to a close enough proximity.

They are less than $20, available everywhere, and they are fun & promote basic safety when working around live circuits.

../Wayne C.

:)
 

bigjohn67

Senior Member
Re: The owner was upset??

These testers were only meant to replace the old neon testers we use to use on knob and tubing to identify the "hot" conductor.
I believe the use of these devices will someday get someone hurt.

Ive seen people use these to test out houses before. Gee, what if there was a loose neutral somewhere. These testers are dangerous.

Just my opinion
 

hurk27

Senior Member
Re: The owner was upset??

There is only two things I found useful for these and I have two one is an early model green lee with a sensitivity adjustment the other is a newer smaller one. the older one is ok for tracing wire in walls the newer one is small enough to place in or around a JB box that might get turned on because of others in a building and act like a warnning device. but they are worthless for trouble shooting as they will falsely detect current on wires that are not connected from emf leakage.
 

cwsnsons

Member
Re: The owner was upset??

Hurk, Exactly my sentiments. Many people use these as a definitive tester. We have them, have for about 12 years. But I tell the boys that they have a VERY limited usefulness, sort of like a first line. As was stated they can give erroneous indications, especially if the circuit you are testing parallels another that IS energized, and due to inductive coupling, there is a SMALL voltage induced in the conductor under examination.

A couple of WARNINGS about these wonderful tools:

1. If you're checking a 220VAC cable, they don't usually indicate a live circuit, even when the circuit IS ENERGIZED! I think that's because the 220V with 2 Hots flowing in opposite directions produce mutually-canceling opposite fields; thus no net effect to trigger the sensor.
2. They WILL NOT DETECT an energized circuit in a cable in which the conductors are spiraled/twisted, or as in the case of SER/SEU types, effectively shielded by the neutral being twisted around the other conductors. ( I ruined a brand new $35 pair of lineman's pliers cutting a 10-2 220V branch circuit cable that had been pronounced "dead" by my helper using one of these when I asked him if the breaker had been turned off. - I know, should have checked it myself!)

Still in all as any tool a professional uses, correctly understood, they do have a use in the workplace. The problem comes in when
does not understand the tool or the situation in which he is trying to use it.

These are another example of an item that generally is not safely useable by the basically uneducated DIYer who sees it at L/HD and picks one up with his supplies for that weekend project.

Chris
 
G

Guest

Guest
Re: The owner was upset??

You're right. Their function is very limited. I employ other safety practices in addition to this nifty gadget. I make sure a circuit is dead, but if this tester sings it makes me double check the circuit before placing myself at risk. In my experience this device will give more false positives than false negatives. It's the positives that will kill you (meaning a powered circuit). It's just part of my triple check before I enter into contact. I also try to use bare-handing techniques so that even if I miss a live circuit I won't have a path through my body to ground. Knowing how to bare hand is the safest way to approach electrical interaction.

../Wayne

[ September 11, 2003, 01:42 PM: Message edited by: awwt ]
 

jimwalker

Senior Member
Location
TAMPA FLORIDA
Re: The owner was upset??

back to this picture.Just how did it manage to get this bad before the meter reader turned it in ? Early warning would have earned it some duct tape or even some paint.
 

hurk27

Senior Member
Re: The owner was upset??

Jim this type of installation looks like one around salt water. I have seen some just like this in south Florida. It dont take very long for salt water spray to distroy metal. but like you said it should have been caught before it got this bad.
 

jimwalker

Senior Member
Location
TAMPA FLORIDA
Re: The owner was upset??

I do know what salt water can do.I was the electrician at a marina in Naples right on the gulf for 6 months.That salt spray will destroy everything.Made me sick seeing water come within 2 feet of brand new panels on the docks.This was about 8 years ago and was just a major storm.They were WP but far from water tight.
 

hurk27

Senior Member
Re: The owner was upset??

At my dad's place in key largo we went to all stainless housing type service panels. Then we used alot of dielectric grease to coat the buss bars and anything else that could be croded by salt water these panels were water proof too. but with the cost of them we didn't want to take any chances. never had a problem after that. Now there are PVC housing service panels availible. which will cut the cost. These are also water tight but any connection to the panel has to be kept water tight. most of the PVC units have connections for PVC pipe.
 
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