AC Line Noise

[luudee]

I have a rather large UPS (APC) that backs up my various computers, and some lights.

It works just fine ...

Lately, there is lots of construction going on in my neighborhood, and my UPS takes over

quite often (it is setup to send me emails every time it takes over). The UPS also write a

log file, with min and max input line voltages.

Looking at the log file, the input voltage is within very reasonable range +/- 5%.

So I suspect, the UPS takes over due to noise on the line ...

So I wonder, would a large EMI filter (something that can handle 40-50A) help

resolve this problem ? I suspect it is due to welding equipment and perhaps

some other large electrical motors being turned on/off ... I'd like to clean the

line up as much as possible ...

Any pointers suggestions appreciated !

Thanks,

luudee

[Pib]

Putting some whole house or power strip surge protection on your line may help, if it's surges/spikes causing your UPS to kick-on. I expect welding machines/big motors would definitely create some healthy voltage spikes but these would probably be in the milliseconds ballpark. But if your UPS is like most surge protectors, it only takes a voltage irregularity of 5-15 milliseconds to cause them to kick-on. If you UPS comes with surge protection, maybe it just ain't good enough and additional surge protection is needed.

Installing a whole house surge protector on your main circuit box/consumer would be better than power strip protection since the surge protection built into power strips is usually only between the Line/Live wire to Safety Ground or between Line and Neutral versus being between Line to Earth, Neutral to Earth, and Line to Neutral. But I expect if it is surges/spikes coming in on the Line/Live wire versus the more rare Neutral or Earth generated surges like caused during Lightning storms.

If you already have good Surge Protection, then just consider this a well intended post. Cheers.

[Pib]

This webpage/link has some helpful info on power quality and equipment protection.

[luudee]

Thanks for all the pointers guys !

I have ordered a Schaffner FN 258-55-34 3-Phase filter online ...

Hope that will help !

Thanks,

luudee

[Crossy]

That's a beast of a filter luudee, how much did you pay for it?

It will certainly take the edge of any spikes on the supply, please report back on it's effectiveness in your situation once it arrives and has been installed.

[luudee]

Well, mouser and digikey list it for about $350 USD, I was able to find a new

unit on eBay for $200. If it will fix my problem, I think it will be worth every cent !

luudee

[bankruatsteve]

Just curious... sounds like you have ordered from ebay, etc. before - so, does it just get delivered to you no problem or do you have to do a run around with customs?

??

[luudee]

I order lots of stuff on eBay ...

It all depends how the items are declared. If it's less than $100 USD, it is usually free of customs.

If the declared value is higher, I have to go to the post office and pay duty + vat (typically 10% + 7%).

I have also had packages randomly inspected by customs (Lam Chabang). It's a trivial process,

just a pain in the neck to drive all the way out there. They just ask you to open the package, inspect

the contents and any paperwork inside. Smiling and being polite always makes the entire process

easy ...

luudee

[luudee]

FYI, just got back from Lam Chabang customs office today.

The nice folks processed my package (roughly $1800 USD, but warned me

that next time, if my package is over 40,000 Baht, I must file a import declaration.

They also indicated that that was a complex process and I most likely would

have to hire one of the service providers for that.

So it might be worth sending stuff over 40K baht with FedEx or DHL, or UPS,

as they will do all the paperwork for you (and charge you of course accordingly).

luudee

[Pib]

FYI, just got back from Lam Chabang customs office today.

 

The nice folks processed my package (roughly $1800 USD, but warned me

that next time, if my package is over 40,000 Baht, I must file a import declaration.

They also indicated that that was a complex process and I most likely would

have to hire one of the service providers for that.

 

So it might be worth sending stuff over 40K baht with FedEx or DHL, or UPS,

as they will do all the paperwork for you (and charge you of course accordingly).

 

luudee

Is this the item you bought off ebay for $200?

Sent from my Samsung S4 (GT-I9500)

[luudee]

FYI, just got back from Lam Chabang customs office today.

The nice folks processed my package (roughly $1800 USD, but warned me

that next time, if my package is over 40,000 Baht, I must file a import declaration.

They also indicated that that was a complex process and I most likely would

have to hire one of the service providers for that.

So it might be worth sending stuff over 40K baht with FedEx or DHL, or UPS,

as they will do all the paperwork for you (and charge you of course accordingly).

luudee

Is this the item you bought off ebay for $200?

Sent from my Samsung S4 (GT-I9500)

Obviously not. Dhuu ....

[Pib]

FYI, just got back from Lam Chabang customs office today.

The nice folks processed my package (roughly $1800 USD, but warned me

that next time, if my package is over 40,000 Baht, I must file a import declaration.

They also indicated that that was a complex process and I most likely would

have to hire one of the service providers for that.

So it might be worth sending stuff over 40K baht with FedEx or DHL, or UPS,

as they will do all the paperwork for you (and charge you of course accordingly).

luudee

Is this the item you bought off ebay for $200?

Sent from my Samsung S4 (GT-I9500)

Obviously not. Dhuu ....

I wasn't sure...thought maybe you had been hit with a HUGE customs charge but just a very calm person.

[luudee]

...

I wasn't sure...thought maybe you had been hit with a HUGE customs charge but just a very calm person.

Sorry, didn't mean to be rude, just didn't know how to interpret your post ...

luudee

[luudee]

Well, the filter arrived today ! This was a very quick EMS delivery. Ordered Aug 29, only 11 days to get here !

Import duty and vat: 1062 baht (declared value was 6000 baht).

Of course 3 days ago the line noise issue U had went away ... I guess we all are familiar with Murphy and his laws ... lol

Anyway, this thing is HUGE ! Attached is a pick with a 20 baht note for reference !

luudee

[Crossy]

Make sure you hook it up in line with the instructions, particularly with regard to the grounding requirements, it's the quality of the ground that determines how efficient the filter is at snubbing the nasties.

Installation instructions are on the Schaffner website if you didn't get any.

[luudee]

I order lots of stuff on eBay ...

It all depends how the items are declared. If it's less than $100 USD, it is usually free of customs.

If the declared value is higher, I have to go to the post office and pay duty + vat (typically 10% + 7%).

I have also had packages randomly inspected by customs (Lam Chabang). It's a trivial process,

just a pain in the neck to drive all the way out there. They just ask you to open the package, inspect

the contents and any paperwork inside. Smiling and being polite always makes the entire process

easy ...

luudee

Sorry I was incorrect about $100 USD being free ...

Up to 1000 Baht is free ... here are the rules (as of today ;-):

luudee

[Forkinhades]

^ would like to see the manual of that

[luudee]

^ would like to see the manual of that

http://www.schaffner.com/en/products/emcemi.html

Scroll down until you see "FN 258" ...

luudee

[luudee]

I just realized that Filter I got, only covers the 3 phases, not the

neutral line. Do you guys think that will be an issue ? As far as I

can tell, the neutral runs on top of the 3 phases on the pole, and

is than grounded by the meter (it's the last pole in the street).

Also, my AC mains enter my garage first. There is a large 3 phase

circuit breaker. Thank I split up power to the pool pumps, well pump,

etc., and to the house. I think I want to install the filter after all those

pumps. The wiring to my house is roughly 10 meters of 16mm^2

cable. So I'm thinking to install the filter in the wiring closet of my

house instead of the garage. Does this make sense ?

Thanks,

luudee

[Crossy]

If your installation is MEN (as it probably is from the grounded neutral) a good solid ground connection will provide the filter with the best chance.

Do you have a N-E link somewhere?

Install the filter as close as possible to the N-E bond.

Post some images of the various bits of your installation for a better response.

[luudee]

If your installation is MEN (as it probably is from the grounded neutral) a good solid ground connection will provide the filter with the best chance.

Do you have a N-E link somewhere?

Install the filter as close as possible to the N-E bond.

Post some images of the various bits of your installation for a better response.

Sorry, I do not know what MEN means. Googling it did not get me an answer either ...

I have a solid earth rod in the house, that we put in when we where building the house.

It has worked well in the past.

Thanks,

luudee

[Crossy]

MEN is Multiple Earthed Neutral look at TN-C-S here http://en.wikipedia.org/wiki/Earthing_system

Have a look for a link between your incoming neutral and the earth rod, new installations are supposed to be MEN.

Either way a good solid earth to your main earth terminal will do the trick.

[luudee]

Thanks for that link Crossy !

So looking ta that website I have a "TT" installation. There is no link between

Neutral and Earth (anywhere). I was wrong about my previous statement that

Neutral was connected to Ground at my pole.

I have an independent ground inside my house ....

So it sounds like I should have gotten a filter WITH Neutral filtering ... :-(

Thanks,

luudee

[Pib]

My home and probably my entire 750 houses moobaan here in western Bangkok which has pretty much been built by the same developer over the last 20 years or so is a TT grounding area. My house is almost 6 years old. You have your earth ground at the house but it's not connected to your neutral at your service entrance or CU. The only place I see the neutral line grounded to earth is at the transformer poles.

Sent from my tablet

[luudee]

My home and probably my entire 750 houses moobaan here in western Bangkok which has pretty much been built by the same developer over the last 20 years or so is a TT grounding area. My house is almost 6 years old. You have your earth ground at the house but it's not connected to your neutral at your service entrance or CU. The only place I see the neutral line grounded to earth is at the transformer poles.

Sent from my tablet

Yeah, it appears this is the same setup as I have as well.

luudee

Edited September 13, 2013 by luudee

[luudee]

I just checked again, and at the Pole the Neutral IS connected to Earth after all.

Sorry about all the confusion guys. Attached picture. It's a bit hard to see it's a

bare woven steel wire, the last 3 meters are in a yellow plastic pipe ...

So it is a modified TT connection, where N is also grounded at the

final customer site ...

luudee

Edited September 13, 2013 by luudee

[Pib]

Looks like the reason your pole is grounded to earth is because it looks like the electric company has put transient voltage suppressors (TVS) on the 3 voltage carrying lines to provide lightning strike surge protection at that point on the lines with the TVSs grounded to earth at that pole. Are other other nearby poles grounded...or just yours?

[luudee]

No the other poles are not grounded and also don't have the TVS on them.

Could this also be because this is the "end of the line" ?

luudee

[Pib]

Could be...I was thinking about saying that in my earlier post since I saw that diagonal support cable on the pole. The electric company could put TVSs anywhere along the line and I expect the transformers have TVSs also. In my moobaan only the transformers have TVSs or Metal Oxide Varistors (MOV) which is basically another name/type of surge/lightning protector. Having TVSs/MOVs at the end of a line makes sense to help ensure the surge is suppressed even at the very end of the line. Kinda like terminating a RF transmission line to ensure you don't cause reflected RF waves on the line which can cause major signal problems on the line.

Also even for a house that has whole house surge protection installed at the electrical service entrance or CU, if there is more than 30 meters in electrical runs feeding various parts of the house after the CU many surge protection companies recommend surge protection be at the very end of those runs also...like a surge protected power strip. Now of course those companies want to sell more of their surge protection products but it's a fact about a significant voltage surge/spike can be induced onto the electrical runs in the walls between your surge protected CU and electrical outlets around the house by a nearby, strong lightning strike.

Example: say you had over 30 meters of electrical run between your CU and another part of the house, well, during nearby, powerful lightning strike a surge in the lines can be caused by "induction" in the house lines even if the lightning didn't physically strike any outside electrical lines feeding the house....the long lines are pretty much acting like a long wire antenna which allows the surge/high voltage to be inducted onto the lines. And many of the lightning surges riding on the electrical lines feeding the moobaan soi's is not from "direct" strikes to those lines, but from "induction" because the electrical lines feeding/running around your area is just a bunch of long antenna wires on poles.