Electric meter question

I already told you - a center tapped transformer. That is tough for me to explain further without pictures etc. I don't do well with text.

 

.........

 

My buddy from Australia (where they have 220-to-ground, single-wire system) - had an irrigation pump go down one night.

He called me and I grabbed my Wiggy and tool pouch and went over to see the problem.

I was checking out the motor feed (3-wires , 240 3 phase) and the Magnetrol was only seeing legs #1 and #3, with no power showing on leg #2. Naturally, the Magnettrol won't hold under such a situation, and as I was tracing backwards, heading to the supply lines, the local Co-Op electrical truck expert shows up and says that the are 'seeing' a problem on their computers and came out to see what's happening.

Well - I stepped back, allowing this 'expert' room in the small pump shed to do his thing and I went out to sit on my tailgate.

He walks out and says there's a blow-out inside the conduit (a red flag goes up in my mind) and that a leg is fused to the conduit, going straight to ground (red flag #2).

He says to pull the wires out of the conduit - and "Oh, by the way, why don't you replace that old aluminum wire with some nice new #6 AWG copper and a #8 AWG ground while you're at it".

"OK" I figgered, conceding that he was the expert and I hadn't completed my examination at that point and I might've come to the same conclusion if that was what the trouble was anyway.

We went and bought 65 feet of three runs of #6 copper plus the #8 ground and when we got back, we pulled the old aluminum outta the conduit. The 'expert' had already DCd the three plus the old ground of the old #4 aluminum inside the bottom side of the meter box on the pole.

There was no 'blow-out' in the wires, and since the conduit was NM anyway, I knew there wasn't any short-to-ground there either.

Hmmmm - I thought ---- why did this guy want to tell us that the aluminum wires were bad?

We pulled the new copper in and when I opened the pole-drop to final the connex, the acrid burnt smell knocked me in the sinuses.

I asked my buddy how he knew the fuses were bad, and he said he changed them early this AM, but it didn't help and he did them another three times, not fixing the problem.

The screw clamps on the bottom of #2 leg was burnt so badly that the Bakelite stunk from the resistance-heating of a bad connex! This was the trouble all the time - just loose aluminum wires in the bottom of the SquareD connex on the customer's side of the fuses.

After buying copper wires and pulling out perfectly good, but loose - aluminum wires and then finding the trouble was the electric company's responsibility all along just set me in a bad mood.

I haven't said anything, for my buddy's future dealings with the CoOp, but if it was MY system - I'd keelhaul that 'expert'. I cannot in any faith ever trust the CoOp 'experts' again.

FWIW: I worked with 240 and 480 3-phase at the hospital I worked at in Los Angeles, and although I am not an expert, I can certainly come to a correct conclusion if I am allowed the time to work backwards on a failed circuit.

I had to 'help' with the 25KVA in the transfer room a few times, and really 480 scares the [email protected] outta me.

230 3-phase is not as dangerous, although a lot of sparkys have zeroed-out from it.

25 KVA is Satan's electricity and if you don't keep it busy doing something, it'll jump out and grab you!

 

Not really "wonky", it would be 208V.

 

The transformer is really a single phase transformer with the secondary winding at 240V, the neutral is tapped in the center of the winding. So from one end to the center of the winding is 120V, the other end to the center is 120V (each of the 120V "legs" are 180* out of phase).

Think of two (2) 1.5V batteries in series, take the black lead of the volt meter in connect it where the positive of one battery contacts the negative of the other (a "center tap"). Then connect the red lead to the (remaining) negative of the battery - you will get -1.5V, then move the red lead to the (remaining) positive of the other battery you will get +1.5v, then move the black lead to the negative of the battery (not contacting the positive of the other battery - end to end) and you will get +3V.

 

The first sub-division in Memphis to get air conditioning used commercial type AC units, which were 240 delta systems. So each house had two (2) services - a 240 Delta (Power Bank) for AC, and a 120/240V single phase for lighting and dryer/ovens/stovetops.

When the S/D was converted to underground primary, removing the overhead system, special transformers were ordered - two (2) 15 kVA secondary windings and one (1) 25 kVA secondary winding in a delta configuration. The 25 kVA winding is center-tapped. The primary windings are configured delta. The primary windings are fed with two (2) phases of WYE connected primary (feeding the primary of the transformer as an open delta).

The output of the transformer (fed from two (2) phases of primary) is 3-Phase 240 Delta (at about 8.4 kVA) and 120/240 single phase (at about 16 kVA). Both the single phase and three phase services are fed from the same transformer.

The most "unique" power transformer I've ever seen.

Edit: Another unique transformer was the wye 139/240V (a underground fed padmounted transformer replacing an overhead 240 delta power bank)

 

I saw a trailer for a movie called "The Current War" today. You might want to watch- it pretty much gave the same impression. IMDB has it listed as a 2017 movie. I guess "Saataaan" must have some involvement.

 

View: https://www.youtube.com/watch?v=mpgAVE4UwFw

Long video but good. At 34:50 grounding myths are discussed.

It is and an extra ground rod is not needed. Pounding extra ground rods all over the place does no good.
At 49:57 is a little bit on generators

 

The ground rod still dissipates static if it was a generator. Lots of ground rods is good in general, it lowers the overall impedance of your ground which can help with things like lightning.

 

No, unless there is a power surge (e.g., lightning).

With single phase (residential), the two 'legs' always carry a balanced load of 120v (110) each, and the meter has nothing to do with regulating this voltage; however, beyond this, what I know about the meter's workings would not even come close to filling a thimble, so I am done here.

Good luck with solving your quandaries.


PW

 

Yeah.... I like Cutler stuff, but it had Square D in the room and I'm not gonna run his $$$ up any higher than that idiot CoOp 'expert' did with his bad diagnosis.

The well house stuff's been up-n-running for over 20 years so far, so-o-o it MIGHT be OK for a while or OK until he gets all his hay into the barn and makes a little more $$$ to replace it.

Aluminum wire sux though if one doesn't at least provide a modicum of maintenance by running all the screws up to torque every 6 months or so.

We get some extreme temp swings from -20F to (like today) 82F. I can see aluminum squishing that way.

I wonder how many new motors have been installed when it's just a bad leg on 3-phase aluminum? If I made that bad of a judgement call, I'd have been fired for gross stupidity.[/QUOTE]

 

That is what was taught at one time but not now.
Myth 4 - More grounding is better is at 9:22 in the video.

View: https://www.youtube.com/watch?v=qNZC782SzAQ&t=260s

 

So they are right why? They are on the internet?

 

In this case there is no "what was thought", better ground is better ground. What that means can certainly depend, in some cases it may create more problems than it is worth.

 

I think he explains very well in the video why he is right and you just wont find anyone claiming he is wrong. Mike Holt is a giant in the industry and is recognized as an expert among experts. You will find all sorts of references to him from various sources for answers to electrical questions, answers to NEC code questions, and for education and training. He has a lot of good training videos on youtube that are easy enough to grasp for most. A lot of people think a ground rod protects against getting shocked. And most don't know that their if children weigh under 50lbs a GFCI wont trip and they can still be killed. Electrical safety is what most people should at least watch. Here is something on swimming pools.
https://mazzapoolinspections.com/bonding-pool-safety/

 

The first video is unrelated, he is talking about machines and use a ground rod to create whole fault and as he says that does not work. That is not relevant when using a GFCI. The other the section you pointed to, he does not know what he is talking about and just parroting NEC code. It is more complicated than he says. The answer as always is - it depends. For dealing with outlets outside run GFCI. I have never heard of the children under 50 lbs before, weight has little to nothing to do with it and besides I have tripped GFCIs before and felt nothing at all.