Japan questions

[dbroekema]

I just moved back to Japan, brought an amp, and thought I'd poll the braintrust here on a couple of issues.

The most pressing one is grounds. Most household outlets in Japan are ungrounded, unpolarized two prongers. Outlets that are near appliances have a screw-down ground terminal (like on a record player), but in our spot these are all taken by the appliances (fridge, washing machine, etc) or are really inconvenient (the toilet room). There are two things I thought might supply a spot for grounding the amp- there are disused phone jack hook ups and old fashioned cable TV coaxial terminals all over the place. Would either of these (probably the steel box inside the phone hook up or the threaded sleeve on the cable coax) make a decent ground? I realize I'll have to use a meter to determine the hot slot on the two prong outlets and mark them.

I remember touring here with a US amp years ago, and just flipping the plug until I didn't get shocked by the mic, but I'd like to do this properly this time!

The other issue is voltage- the US is 120+ and JPN is 100. I've both used a step-up tranny and not, what are the thoughts on just running an amp on 100v? The amp in question is an AC15ish home-build combo, will be used mostly for bedroom volume noodling but there's a slight chance of some club gigs I guess. I'm guessing filament voltage/tube longevity would be the primary worries?

Thanks!
Dave

[kagliostro]

I don't like the idea to connect the ground where it isn't planned to be done

What will happen if antenna or telephone connections are electrically connected with other  electrical installations or other in other apartments

if something goes wrong on your amp and line is shorted to the fake ground ? People and apparatus on other appartments may be damaged

more, I dont' think to those cables as good ground (if they are a bit and I doubt about)

Can not arrange a ground connection on the same place where are connected oven or other electric installations ?

Franco

[drgonzonm]

Using search criterium "grounding plug japan"   I found the JA1-15P, plug adapter. 
Buy one, it should have a grounding wire with it. 

Then I would look to see if plug box is metal.  Then determine if it is grounded.  I would then check voltage to box with a decent voltage meter.  My favorite is a neon test lamp.  Find out which one is hot and the other neutral.  You can then wire the ground to one of the screws. 

Remember, in the us, our green and white wires actually meet at the panel. 

For a voltage voltage boost, find a 120/12-24 or a 120/6-12 transformer.  then wire it to boost rather than reduce using S Luckey's vintage step down transformer found on his site, "scrapbook" 

[PRR]

> a screw-down ground terminal .....all taken by the appliances

You can put more than one ground wire on a ground terminal. Adapt to 3-pin and use 3-pin extension cord to a 3-pin multi-outlet in the playing room.

TV outlets are NOT reliably grounded. TV techs are even more casual than electrical techs. While you might think it needs shield continuity to "work", there can be many Ohms in there without much loss of TV signal.

[dbroekema]

Thanks guys, I'll do it the safe way this time! Plan to use the outlet behind the fridge and just run an extension off it. Need a cheap meter to determine the hot terminal.

[dbroekema]

Any thoughts on running at 100 vs 120v? If I opt for a step-up tranny, how big should I go for an amp of this size?

[PRR]

I do not know why you want to "find the hot terminal". In a 2-pin land, I would expect *either* side to be hot.

Simply treat both non-GroundED pins as "live".

US gear designed for 117V will be unhappy at 100V. Possibly damaged.

What do the local players do to use US gear? Draw a picture of a Japanese house "100V", a lump "?", and a gitar amp labeled "120V". Work your way around the electronics shops.

> how big should I go

AC15 may get by with 100VA. 150 or 250VA may be a better investment.

[sluckey]

I've never tried this but it may be a cheaper solution than a stepup transformer. Look at page 2 of this pdf. Wire the filament transformer to boost rather than buck...

     http://sluckeyamps.com/misc/Amp_Scrapbook.pdf
 

[kagliostro]

Step Up transformer is a good idea

Or get one of this

http://www.frys.com/product/8070364;jsessionid=tPJ0SBcpqqnwK+ZBFFlmjA__.node1?site=sr:SEARCH:MAIN_RSLT_PG



https://www.amazon.com/VCT-VT-500J-Japanese-Transformer-Converts/dp/B000PC4JL4



Franco

[drgonzonm]

I do not know why you want to "find the hot terminal". In a 2-pin land, I would expect *either* side to be hot.

I guess one could use a "polarity switch and the death cap"  NOT RECOMMENDED

By knowing which is neutral, you can use it as your grounding.  (hence the note that neutral and ground meet at the panel box).   I grew up in a house that was built in the 30's and a rental in the family had 3 wire service at 60 amps, also with two prong plugs. 

[kagliostro]

By knowing which is neutral, you can use it as your grounding.

Here in Italy that is higly forbidden

Franco

[sluckey]

Here in Italy that is higly forbidden

Same in the USA.

[drgonzonm]

Here in Italy that is higly forbidden

Same in the USA.

Don't disagree.  Yet if you look at poles, it is the neutral wire that is sometimes (suppose to be) grounded.  (with the price of copper, it is common to find poles that are not properly grounded, because someone stole the ground wire. 

[Ritchie200]

Even though the pole wire might be missing, the home/meter base ground rods and plumbing grounds are there to bring the building ground as close to the local potential as possible.  There are always grounding issues at the pole as well.  A few pole wires missing here and there will not be a problem. 

As you mentioned, grounds and neutrals can only be bonded back at the panel in the US.  Bare wire to the closest water line does not count nor does a jumpered neutral/ground at the outlet or just as bad, actually in the appliance.

Dave, you mentioned this is a home built AC15 type combo.  Does the power tranny have any other primary taps?  If not, instead of buying all sorts outboard gear, just pop in a new power tranny that will accommodate 100v, change the cord, and call it a day.

Jim

[kagliostro]

Bare wire to the closest water line does not count  ........

Well, many years ago (I don't remember exactly, may be 30-35) I was in the shower and I was washing me, at one point (can not remember if in

that moment I was touching a tap but I was under the water) I had the extreme pleasure of a beautiful electric shock (here we have the line at

220V), I assure you it was not a pleasant, due to a problem to the engine fan of the boiler of my neighbor

I highly distrust anyone to connect ground wires to the water pipes, I think you can understand the reason

Franco

[drgonzonm]

Wide guess time,  put an arc fault breaker in your amp or your step-up transformer and install a death cap, and a polarity switch.  The arc fault should trip the breaker if the death cap should fail.

Franco, don't play guitar barefooted on a concrete floor it is not pleasant.  To stop the shock in Florida, we had to soak ground around the ground rods to cut shocks.  Two ground rods were installed as per NEC.  ground in central Florida beach sand.  During winter, when you don't have much rain, the conductivity the soil goes to pot. 

Another option, read expensive, is to use wireless transmitters to get your signal from the instrument or mic to the amp.  No path no shock. 

Franco, I received many shocks in the field when it was damp and misty when pressing activiation buttons.  The electrical guys told me, it shouldn't happen, but it did.  Very unpleasant

[kagliostro]

My uncle job was about gas pipe protection against stray currents in the soil

when the gas pipe was crossing some rocky journeys to give a decent ground was a pain, he told me they used an auger to make hole

in the rock, then put on the ground pole and fill with charcoal and copper sulphate granules (and water), despite this in some place the

ground connection was near unacceptable

Franco

[PRR]

> ground wires to the water pipes

Historically, in the US, city water was underground metal pipe over the whole town. This was a VERY good earth connection.

When I investigated this in my last city-water house, I discovered that the copper pipe through the wall stopped a few inches out, the run to the street was new plastic.

Water companies objected to bonding, and some water meter techs have been killed by customer mis-wiring. But water-pipe ground is so good that water men and NEC have come to tenuous agreement, emphasizing a jumper around the water meter so it can be replaced without breaking electrical connection. 

I jumped my meter, even though the far end was just a few inches in dirt. Not enough to absorb a major fault, but plenty to shock a water-worker.

Gas pipe was historically metal, though gas companies objected to bonding. I had gas put in, and noted that again it was metal only above ground, the run was plastic.

In that house I discovered an abandoned water system under the kitchen. Copper and *lead* pipes in semi-damp ground, and the stub end convenient to my indoor metal pipes so I jumped it.

Do note that a "shower" is really two pipe systems. Clean water spout, dirty water drain. Old drains were clay, but later a lot of copper was used and sometimes iron far into the ground. Main street drains were typically clay, but in un-stable soil these may have been upgraded to iron.

So it "is" possible to have the spout and the drain at different voltages. (And I have never seen a rule to suggest bonding drain pipe.)

> a problem to the engine fan of the boiler of my neighbor

If ALL the connections were correct, a hard-short in the equipment would blow a fuse, a part short would not induce significant voltage in the plumbing.

There are many ways the wires can be shockingly incorrect, but the lights (and boiler) work fine.

[Ritchie200]

Yeah the plumbing ground I was referencing was bonding where the water line enters the home, jumpering the water meter.  Also provides a good reference for GFCI operation.  Back in the day they would run to the closest pipe. 

Typical cast iron drainpipe in the soil under the house usually changes over to clay outside - unless its really old!

Funny you mention gas pipe bonding...  The yellow jacketed CSST gas lines MUST be bonded to the ground at the panel.  Turns out some bean counter was in charge of specifying tubing thickness (yes I'm kidding but have witnessed similar executive decisions..).  Close by lightning strikes will blow little pin holes in the tubing.  Bonding the product solves that issue.  The new grey jacketed CSST is fine.   

Jim

[PRR]

> CSST gas lines MUST be bonded

Yes, I missed that, new (skimpier?) technology brings us new faults.

I know what you mean about beancounting. I'm not sure that is the case here. More like we don't have enough data for lightweight metal UNDERground (should be safe?) around Lightning strikes (rare and come in all sizes). Oh, maybe we have data for telco and ethernet lines in lightning country. But they don't blow up, so statistics may be sparse.

Just shows it is impossible to know everything. We come up with Rules, which may be wrong (non-grounded power was favored as recently as 102 years ago), and eventually enough bad happens that we re-consider the rules (grounded power supply is the Base Rule in all but strange situations).

[PRR]

> reference for GFCI operation

The basic GFI operation does NOT reference Ground.(*)

Older GFIs outlets didn't even touch ground except to make the green feed, U-hole, and bracket connect. GFI for in the fusebox doesn't have a green wire.

GFI works on the -difference- of current in Live and Neutral (or Neutral and Live- it don't care).

(*) Yes, in recent years stock GFIs "do" sense Green, trying to detect Bootleg "Ground". If you tie Green to White at the outlet, it will fool a 3-light outlet tester. But if the white later comes loose on the way back, you have a VERY dangerous condition. Your amp is dead but the chassis is hot, and the GFI will not protect you. They apparently now put a high frequency tone on the line, to see if the white-green path is several feet (probably OK) or just a few inches (probably bogus and dangerous). I had trouble with this when trying to put a GFI outlet next to my fusebox: some GFIs sensed 3 feet as bogus. Now I know, I could zig-zag a few more feet on a joist before the GFI.

[kagliostro]

When I told about the job of my uncle, the gas pipe to which I refer was the large gas pipe the company use for distribution, not the small pipes that reach each house, the large pipe are feed with some dedicated power supply (expecially near train rails to avoid the stry currents coming from the stry currents due to the electric engine of the trains) to avoid the perforation


On the small gas pipe that are on each house tere is the obligation to put a dielectric joint before the pipe go under tre soil to avoid electricity propagation on the pipe, so no good ground due to the fact it runs underthe soil (expecially now that under the soil there is most plastic than iron)


The rules want that the gas pipe is connected to the ground pole as to obtain equipotential and avoid the connection of equipment grounds to it


Franco

[Ritchie200]

Sorry I meant to say ground fault, GFCI just came babbling out because we were talking about it... A ground fault with a floating ground (outlet ground wire to closest water line and not back to panel) could have enough resistance to prevent or delay a breaker tripping while energizing the appliance (amp chassis) in a bad way.

Yes GFCI does reference the neutral side for mismatch which is why you can use them on a two wire system.  Of course you should put the "No Equipment Ground" sticker on it - which never happens...

Jim

[drgonzonm]

> reference for GFCI operation

.....

. GFI for in the fusebox doesn't have a green wire.

GFI works on the -difference- of current in Live and Neutral (or Neutral and Live- it don't care).

......

I am sure you are correct, but aren't the ground and the neutral tied together in a main panel?.   I know that sub panels are becoming more and more common.

Given the price difference between gfi in the panel and one in the kitchen/bath, the wall outlets are significantly cheaper. 

After some perusal, I agree with Ritchie. use a gfi.  I would also get permission from the owner of the place before installing one. 


Additional comment regarding lightning.  Very strange, Very strange.  Some of my fellow students, (physic majors), coop'ed at  New Mexico Tech's Lightning Research Center, high in the mountains, west of Socorro.  While working on 2 inch cable stretched across a canyon, the cable was struck by lightning, a quarter turn in the cable saved their lives, as the path to ground changed.

I routinely check utility poles for grounding,  (too much time in the lightning capital of the world, central Florida), I have found a minimum of six poles in a row with missing grounds.  Guess where the nearest ground is, the house that's wired into the grid.   In central Florida, we found as many as 20 poles in a row with missing grounds, very rural. 

[EKDENTON]

When I grew up tools looked like this photo metal case no ground., back then houses probably wired even worse. Maybe you could add a ground wire and modern plug to where you plug the amp in? Does the home even have a ground rod at the electric panel?

[drgonzonm]

When I grew up tools looked like this photo metal case no ground., back then houses probably wired even worse. Maybe you could add a ground wire and modern plug to where you plug the amp in? Does the home even have a ground rod at the electric panel?

Read up on gfis, and use a gfi.  As stated in this thread remember to label it about no ground connection   or find a gfi on an extension cord, use it for your amp.  I believe as others this is your safest route. 

[Paul1453]

In Korea which also uses 220VAC 50Hz source voltage,
we simply used the 120V/60Hz step down transformers for our US configured equipment.

I didn't seem to have hum or other issues with any of my audio gear.

I never grounded my step down transformers, and am not sure where I could have found a good ground connection in our apartment. 

[drgonzonm]

Another wild idea suggestion,

Modern hair dryers and curling irons have gfi's installed on their cords.  Find a Modern hair dryer at say the equivalent of Goodwill and use the cord to feed your step up transformer.