George's Power Supplies

[N4LTA]

A UFER ground is a concrete encased electrode developed for the army in 1942 by  Herbert G. Ufer.It makes a very good gound. Normally you have wire or a mat of wire placed inside the concrete foundation with a lead run out for connecting.

The grounding conductor does bleed of any small chage but the NEC developed it to conduct and dangerous current to the ground system and trip the breaker - it is all sort of the same thing.

I saw a system at a church here a few years ago, where the contractor bonded the neutral in every panel and thought he was helping matters.  The church has a CCTV system throughout the facility with multiple cameras etc.

The system was fed from multiple panels and each panel had a different ground voltage - quite a bit different due to current flow in the neutrals of each panel - and his bonds.

The coax had several amps of current flowing in the shields shields - because of the different ground potentials in the various equipment served by differnt panels. You would get a bad shock when removing a coax connector.

Pat
N4LTA

[The Slab Bacon]

A concrete encased electrode ? ? ? ?  that kinda sounds like it defeats the whole purpose of the electrode   

Concrete when dry is a very poor conductor, almost an insulator. Unless the concrete is some special mix with something conductive added to it. You would think some kind of non corrosive (rust resistant) metal in direct contact with the soil would make for a much lower resistance path.  Sounds like a trip to Google is in order..............

The 5 joined neighbors where getting RFI through the Neutral. It was identified here by inspection. Other then that issue, My station passed. Big power contractor style RFI filters for industial equipment solved that.  They have 80DB cut at HF and are available at electrical parts houses.  Its a good idea to install them into transmitters like George here.  Why even chance putting RF into your home?  Those neighbors rarely complained over the years anyays.  But since the inspection found it, I had to fix it.

The shame of it all is that if you and everyone else had a neutral leg grounded with a good ground at the point of entry it would have prolly been a non issue!
the shame of it is that big RFI filters aint cheap and you got stuck paying for them.

[N4LTA]

Concret is always a bit moist when in the ground and a UFER is a very good ground. I suspect that the chemicals in the concete salt the ground also.

Pat
N4LTA

[W2VW]

Churches have a special problem.

People with good intentions who volunteer labor.

Sometimes it isn't easy to balance.

I didn't know NEC was an evil plot to undermine folks with wire nuts and superior intellect.

I learn something every day. Thanks.

[kb3ouk]

I saw a wire nut with a hole burned through the side once from being used in a junction and it overheated.

[KM1H]

Pat, you keep dancing around NEC's forcing revisions when the old way worked fine for decades. Yes requiring 3 wire 120V outlets was a good move and a few other things that were cleaned up. GCFI was a good move also.
But most after that was a bunch of clowns in the electrical business looking to increase profits and creating new reasons to keep NEC relevant. Its the American way with any bureaucracy...form it, couch it in pseudo scientific psychobabble that the masses just blindly nod their heads, bend over, drop their draws and wait for the revelation Pass out the Flavor Aid

A lot of ham wiring is wrong and I mean potentially dangerous. Way too many use a basic 120V cable of 2 conductors and a smaller bare ground (called such as 12-2 "with ground") for a 240V feed since its cheaper....typical ham philosophy.

However using 3 insulated wires of the same gauge such as 12-3 allows the return current to run with out overstressing the wire. All the 4th wire does then is act as a backup while at the same time generating an annoying current between neutral and ground at the equipment end. That 4th wire is a complete BS requirement for probably 99.99% of single family residential installations.  It might be a bit high for double wides

Also since existing wiring is grandfatherd for new appliances should tell you more about the con job. Im sure the always corrupt electricians unions would love to get the feds to require destruction of all non conforming structures.

[N4LTA]

OH Carl!!!!!!!!!!

You are going to scream at this one. Even the inspectors are going off on this one

The new 2012 Code is going to be a bitch.

The new code is doing just exactly what you said.

ALL residential receptacles must be tamperproof and the ALL will have to be Arc Fault - which don't work well and are very expensive.
The real kicker is that in any age house - if a receptacle fails or anything else - it and everything downstream must be brought up fully to code.

That means if your wife yanks the vacuum cleaner cord and breaks the receptacle - you are supposed to call a licensed electrician and he must replace the bad receptacle and all on the circuit with $10 tamperproof receptacles AND install an ARC Fault circuit breaker at $100 bucks or so.

So that old 89 cent receptacle change out will cost $400.

There are lots of people POed and some things may change.


Maybe they will require a PE to sign off on house designs and I can retire a few years early?

Nothing like our dear old government!!!

[WD5JKO]

Looks like the AFCI circuit breaker's often but not always include a GFCI. That means George's power supply if there is ground current won't work once there is a AFCI breaker installed.

The following link discusses the complications the AFCI, and "false tripping". A case where multiple circuits share a Neutral in a junction box might require a home to be re-wired once AFCI breakers are installed. They neglect to say that the sixth reason for an AFCI trip is the Ham Radio guy next door! 

http://www.thecircuitdetective.com/afci_circuit_breakers.htm

So if the AFCI circuit breakers have GFCI, then why not eliminate the separate need for GFCI's? All this stuff has a constant standby power draw.

Jim
WDJKO

[N4LTA]

Jim,

I think the AFCI breaker still cost too much and don't work all that well. The GFCI has been perfected over the years. The AFCI are troublesome. I think they work by detecting RF generated in an arc and lots of things in household have arcs - like hair dryer - when they switch off.

There has been an uproar since the last NEC (2012) was released because of some drastic , expensive changes and my guess is that some of the new stiff will change. The NEC is released and it takes about two years to get adopted.

The last code stopped the common practice of using a common neutral with three phase wires - when using each phase as a single phase lighting circuit or receptacle circuit - you can still do it but only if you use a three pole breaker. I had not heard about that causing the AFCI problems and that might be a reason for the recent change.

The biggie is requiring old homes and establishments to bring existing wiring to current code if something breaks. That is going to cause an uproar when it sinks in.

Carl is right on this new stuff - to much goverment for me.

Pat
N4LTA

[W2VW]

The last code stopped the common practice of using a common neutral with three phase wires - when using each phase as a single phase lighting circuit or receptacle circuit - you can still do it but only if you use a three pole breaker. I had not heard about that causing the AFCI problems and that might be a reason for the recent change.

N4LTA

Hi Pat,

     When was this adopted? I have this exact situation at work and requested the circuits be put on a 3 pole breaker. The electricians said it was up to code on discrete breakers. The circuits were installed in 2011.

Thanks.

[N4LTA]

It was added to the 2008 code I believe. The new codes take about 2-3 years to get adopted by the various jurisdictions. Some here are still using the 2005 code - so he may have been telling you the truth.

We had to change out all the lighting and receptacle breakers in an office building here last years because they renovated more than 50% of it. Had to change them to three pole breakers. I argued with the AHD but to no avail.

Pat

2008 NEC
210.4 Multiwire Branch Circuits
(A) General. Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire circuit shall be permitted to be considered as multiple circuits. All conductors of a multiwire branch circuit shall originate from the same panelboard or similar distribution equipment.

FPN: A 3-phase, 4-wire, wye-connected power system used to supply power to nonlinear loads may necessitate that the power system design allow for the possibility of high harmonic neutral currents.

(B) Disconnecting Means. Each multiwire branch circuit shall be provided with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.

Author’s Comment: There were two reasons for the changes to the text in this section. The first reason was to clarify that all conductors of a multiwire branch circuit must originate from the same panelboard or distribution equipment. The change in (B) was done to emphasize the safety concerns associated with unintentional voltage being present on multiwire branch circuits during maintenance. Deleting the text that applied simultaneous disconnecting requirements for a multiwire branch circuit to a single device or equipment on the same yoke will require simultaneous disconnect of all ungrounded conductors on any multiwire branch circuit at its origin.

[W2VW]

It was added to the 2008 code I believe. The new codes take about 2-3 years to get adopted by the various jurisdictions. Some here are still using the 2005 code - so he may have been telling you the truth.

We had to change out all the lighting and receptacle breakers in an office building here last years because they renovated more than 50% of it. Had to change them to three pole breakers. I argued with the AHD but to no avail.

Pat

2008 NEC
210.4 Multiwire Branch Circuits
(A) General. Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire circuit shall be permitted to be considered as multiple circuits. All conductors of a multiwire branch circuit shall originate from the same panelboard or similar distribution equipment.

FPN: A 3-phase, 4-wire, wye-connected power system used to supply power to nonlinear loads may necessitate that the power system design allow for the possibility of high harmonic neutral currents.

(B) Disconnecting Means. Each multiwire branch circuit shall be provided with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.

Author’s Comment: There were two reasons for the changes to the text in this section. The first reason was to clarify that all conductors of a multiwire branch circuit must originate from the same panelboard or distribution equipment. The change in (B) was done to emphasize the safety concerns associated with unintentional voltage being present on multiwire branch circuits during maintenance. Deleting the text that applied simultaneous disconnecting requirements for a multiwire branch circuit to a single device or equipment on the same yoke will require simultaneous disconnect of all ungrounded conductors on any multiwire branch circuit at its origin.

Thanks again Pat. Time to push the necessary paper to get this done.....

The author's note sparked a bad memory literally.

Neutral from the panel feeds 3 separate 125 volt circuits from a 208Y.

I was installing emergency lighting and removed the wire nut from the neutral feed to a J box and the 3 loads. The other 2 loads were still energized. You know the rest.

[KM1H]

Hey Pat, you just made my day!

From now on you can call me Outlaw Carl

[WD5JKO]

That means if your wife yanks the vacuum cleaner cord and breaks the receptacle - you are supposed to call a licensed electrician and he must replace the bad receptacle and all on the circuit with $10 tamperproof receptacles AND install an ARC Fault circuit breaker at $100 bucks or so.

So that old 89 cent receptacle change out will cost $400.

   So to enforce this, the stores full of 89 cent receptacles need to get rid of them, and make the repair installations by a licensed union electrician a mandate?

If so, time to stock up now, and as long as existing installations are grandfathered until broke, then I will just fix them as I go with NOS parts. So how was this intended to be enforced?


What happened to George? 
Jim
WD5JKO

[N0WEK]

What will probably happen is that people that don't know about the change, when it's implemented, will get screwed when they call an electrician for a small fix and won't do it again.

The rest of us will never call an electrician again. I do careful work and do my research, lots of people don't have any idea what they're doing and don't really care. You'd be amazed at some of the nightmares I've seen, and fixed, over the years in friend's houses.

That said, I think work ought to be done well. I think the changes to grounded outlets, GFCIs and proper grounding/neutrals was a good thing. I may be convinced that new buildings should meet the new code.

Now I may have to buy some extra devices for spares. I already have "pre-ban" "assault weapons", unlocked scanners, R-12 Freon and 100 watt light bulbs. This is getting old.

[N4LTA]

Hey Carl -   I thought you might like that one.

From what I understand  - all residential receptacle have to be tamperproof as soon as the code is passed.

Now we will have to get all of out home receptacle from China undercover!


I think someone is actually making a cheap coverplate that converts the outlet - Its the AFCI that is going to hurt the pocketbook. It's also the retroactive clause in the that is all new.

Pat

[The Slab Bacon]

Hmmmm........... scare people into creating shortages in order to inflate prices.
Kinda like the gas shortage from the 70s. then came the commodity shortages, that was another joke. Everyone was freaking out because there was going to be a shortage of TP next week. Then sugar the following week. First came the shortages, then the prices went up, then the shortages dissapeared..............

When we cleaned out my mother's house last summer I tossed 100lbs of sugar that she had stashed from the 70s. Concrete was softer than those bags of sugar. Not to mention a load of paper products that were so old they had turned brown.


And George, I think he got scared and ran away about 50 posts back  

[WD5JKO]

   Well back to ground current versus neutral current. I did a no-no recently at work. Needed to make a test bench for a 3kw 13.56 mHz industrial grade RF amplifier. So part of that was to test these dudes at +10% line, and -10% line from a nominal 3 phase 208VAC.

   The power was from a 'Y' fed 3 phase, and the RF amp is a delta load. The wiring to the room was to a Hubell 27XX 4 -wire 250V 30A socket. So all I had was three phases and ground...

   In a chassis I installed a 3 phase 15A 240V variac with the windings referenced to ground (the 4th wire). When the variac is on the dot (no buck or boost) the ground current is close to zero. When the load is 15 amps at 229 volts, or 15 amps at 187 volts, the ground current is 1.5 amps (10%).

   So I don't see any fire trucks coming, but I know this might not get a UL approval. How bad is it? I don't know the wire AWG of that ground wire, but I suspect it is hefty.

Jim
WD5JKO

[kb3ouk]

the breaker my shack is on is one of those arc fault ones. i had an AA5 that i was working on one day and tried to hook a ground wire (the shack's earth ground, not AC ground) to it while it was turned on, had a small spark, and there goes the power. that small spark set the breaker off. i'd say that breaker may been a GFCI/AFCI combo breaker.
shelby

[N4LTA]

Jim,

The "Man" is looking for you for passing 1 1/2 amps through a ground wire!

Actually I need to think about that one a little.

The delta load has no requirement for a neutral and neither does a wye with balanced wye load

The variac should have three equal load wired in a wye connection that are balanced at any position.

In theory, your ground can only tie to the frame of the equipment and allow the center point of the wye float. The fact that you have 1.5 amps of unbalance that varies says it may not perfectly balanced or that you have some harmonic load but the amplifier should not care since it is delta connected.

Power companies often use ungrounded wye transformers. In fact almost all Duke Energy transformers padmount transformer are connected  - wye ungrounded :  wye grounded.  If you ask then for a "delta" 3 wire service  - the transformers are connected ungrounded wye.

All discussion here is BS and if you blow up a $25,000 amplifier I will not remember saying anything and will deny everything even you have witnesses.

I'll bet that if you remove that ground wire from the center of the variac - nothing will change


Pat

[WD5JKO]

I'll bet that if you remove that ground wire from the center of the variac - nothing will change

    Pat, you might be right! In the picture from the manufacturer, they had the variac commons bussed together. I went a step further and grounded that bus to the power ground. When I get to work next week I will do some experimenting.

  I hope some of this discussion helped George.

Jim
WD5JKO

[WD5JKO]

Today I looked again at that 3 phase variac. Discovered that the clamp on ammeter was not closing all the way, so it was reading high. So closing it dropped the "ground" current to 1/2 ampere when the variac was boosting or bucking 10%. Put the variac in between (on the dot) and the ground current went to zero.

The load was 15 amps at 187V, and 12 amps at 229V. I got daring and disconnected the ground wire letting the three variac commons ride together, but not connected to ground. The picture of the variac in my last post is how the variac comes new. I did this first without any load on the power. It worked!
Pat your a genius.  I need to do a little more testing, but I think this is the correct configuration, and since there is no ground current, I suppose I am NEC legal.

Jim
WD5JKO

[N4LTA]

Now you don't have to worry about those AHD's sneaking around behind your back.

Pat
N4LTA

[Opcom]

We are talking about a ham install by someone with some smarts, so  trying to spin it doesnt fly Pat.

Most of the morons eliminated from the gene pool prior to GFCI likely had their radio, curling iron, razor, etc fall in the tub or pool with them. Even no coders and CBers are smarter than that.....I think.

Many modern tools and appliances have 2 wire cords

NEC wont even let you enjoy a good tingle these days by limiting line bypass caps to values that are useless for the purpose. Once the nanny state produces rules that protect down to the lowest IQ across the board what will they come up with next? And we will also have a population of breeding morons worse than you can believe.

On the topic of "no-coders" sir, I did not test in the code element because it was not required and I did not have much interest in using CW at the time.

I have not intentionally ridiculed the subsets of which you are a member, especially the subset of CW-users, and therefore I have not ridiculed you personally by association.

What I have done is to have treated you (and everyone else here) with respect even though I do not know you, because I am a gentleman.

[KM1H]

There seems to be a generational gap here.  While Im forced to accept the changes it doesnt mean I have to like them and individual personal insults were not intended.