Electronics Lab Philippines

Academic Community and Professionals => Professional People => IEEE => Topic started by: ram_1121 on September 16, 2014, 04:51:18 PM

Title: Clean out grounding design
Post by: ram_1121 on September 16, 2014, 04:51:18 PM
Guys...need some help...can i use bare copper inside metallic conduit for my clean out ground? is there any implication if i use metallic conduit?or just use pvc?thanks
Title: Re: Clean out grounding design
Post by: tony on September 16, 2014, 05:23:05 PM
if that is a clean ground, why use bare? it should be green yellow wire up to the earthing rod,
at it is not carrying current pvc can be used....depende sa budget mo...
Title: Re: Clean out grounding design
Post by: ram_1121 on September 16, 2014, 05:42:18 PM
i use bare copper kasi it will be from 15th floor down the basement where the clean ground rod will be installed. if i used insulated the size of wire is much bigger compare with a bare copper.
Title: Re: Clean out grounding design
Post by: tony on September 16, 2014, 07:10:50 PM
 hmmm get ready to spend...
Title: Re: Clean out grounding design
Post by: zirlou21 on September 16, 2014, 09:25:22 PM
 :)Hallo(.)(.)there...
 it is not advisable to extend the grounding wire at that lenght,as much as possible sa pinakamalapit na wet soil or ground ang the best connection for grounding to eliminate accumulation of resistane.egagamit ka pa ng copper at 15th floor magkakaroon na yan ng resistance..so hindi na yan clen gound.
...kung talagang malayo sa soil ground ang linya mo,gayahin mo na lang ang PLDT o Meralco grounding,gamit ka ng bare stranded wire with the right gauge to minimize resistance accumulation,
at ipaloob mo sa pvc conduit pababa sa ground rod connection.
Title: Re: Clean out grounding design
Post by: tony on September 17, 2014, 06:12:30 AM
not if you are not using 70mm squared cable...TS wanted clean ground...
while it would be so much cheaper and easier to connect to the nearest metal,
but then it will no longer be clean ground, it will mix with dirty grounds...
Title: Re: Clean out grounding design
Post by: robbietan on November 20, 2014, 12:02:11 PM
a "clean ground" of an electrical/electronic equipment may suffer from ground loops if not bonded to the grounding of the power supply.

if a "clean ground" is needed, there should be no other connections from the bonding of the power supply to the equipment
Title: Re: Clean out grounding design
Post by: tony on November 20, 2014, 12:13:38 PM
a "clean ground" system is composed of earthing rods and cables to instrument equipment...

an "electrical ground"  system is also composed of earthing rods and cables to equipment...

so what is the difference?

the electrical earth connects the metal frames and chassis of electrical equipment to prevent
operators or users of equipment from getting shocked should insulation breakdowns or lightning strikes happen..
the clean earth otoh provides for a zero reference to instrumentation circuits requiring them...

eventually, both the clean earth grounding rods and the electrical or dirty earth grounds are both buried into the earth...
cables running from these rods should never be mixed up along the way...
Title: Re: Clean out grounding design
Post by: Efren Cruzat II on November 20, 2014, 02:05:24 PM
With that distance the wire of that length become a good rf antenna. Uncle bk would be happy to tap from it so he can listen to his favorite radio programs...
Title: Re: Clean out grounding design
Post by: tony on November 20, 2014, 03:16:35 PM
that is why in typical grounding installations such as power substations,
grounding wires are 240 mm squared cables, the bare wires
are formed into a matrix 1 x 1 meter apart and
exotehermically bonded/welded at the intersections...
these earthing cables are layed underneath the substations...
(http://www.maltep.com/154-large_default/bare-stranded-copper-conductors.jpg)
(http://www.maltep.com/155-large_default/bare-stranded-copper-conductors.jpg)
furthe links...
http://en.wikipedia.org/wiki/Exothermic_welding
http://www.erico.com/products.asp?folderid=41
Title: Re: Clean out grounding design
Post by: @badoy on December 04, 2014, 12:15:30 PM
high rise commercial building should have separate grounding for data & electrical. Unless residential building that don't have data grounding provision.

bare copper for electrical and insulated copper for data.

saan kaya gagamitin ni TS?
Title: Re: Clean out grounding design
Post by: robbietan on December 08, 2014, 06:55:08 PM
high rise commercial building should have separate grounding for data & electrical. Unless residential building that don't have data grounding provision.

bare copper for electrical and insulated copper for data.

saan kaya gagamitin ni TS?

separate grounding but bonded at the main transformer secondary
Title: Re: Clean out grounding design
Post by: @badoy on December 09, 2014, 08:55:06 AM
separate grounding but bonded at the main transformer secondary
nope. neutral lines and grounding system are bonded in transformer vault. but data grounding is not. Data Center's don't accept noisy grounding system and especially those connected to electrical system. These can harm your servers and data storage's.
Title: Re: Clean out grounding design
Post by: tony on December 09, 2014, 09:09:03 AM
nope. neutral lines and grounding system are bonded in transformer vault. but data grounding is not. Data Center's don't accept noisy grounding system and especially those connected to electrical system. These can harm your servers and data storage's.

i wish i could post drawings and plans for grounding in the plants that i worked on...
yes, they are completely separate....but like i said, they meet at the ground where earth rods are buried for both dirty and clean earths in close proximity to one another....

(http://image.made-in-china.com/43f34j00vCaQbEtJshcr/PVC-Green-Yellow-Earth-Wire.jpg)
(http://www.taibobo.com/upload/20110615/Yellow_Green_PVC_Wire_Cable.jpg)
(http://image.made-in-china.com/43f34j00qZQEYabCqlkr/PVC-Insulated-Flame-Retardant-Yellow-Green-Earth-Wire-Cable.jpg)
(http://i01.i.aliimg.com/photo/v0/722960105/4_6_mm2_Yellow_Green_Solar_PV.jpg)
Title: Re: Clean out grounding design
Post by: tony on December 09, 2014, 09:13:40 AM
separate grounding but bonded at the main transformer secondary

in a 5 wire system, 3 phases, neutral and ground, the neutral of the transformer is
bonded to earth rods, sometimes thru neutral earthing resistors....
but down the lines, the neutral and ground wires should never be interchanged
with one another, the ground wire and the neutral wires have different distinct roles to play...
Title: Re: Clean out grounding design
Post by: robbietan on December 09, 2014, 09:59:59 AM
nope. neutral lines and grounding system are bonded in transformer vault. but data grounding is not. Data Center's don't accept noisy grounding system and especially those connected to electrical system. These can harm your servers and data storage's.

unbonded systems tend to create ground loops which could damage systems. Have seen it in several customers where they did not bond the grounding of the electrical system to the data system. a lightning strike in the area burned all communication equipment but not the other parts of the computers

ref ANSI J-STD-607-A
Title: Re: Clean out grounding design
Post by: tony on December 09, 2014, 10:19:44 AM
they must have done something wrong in their installation....kaya nasunog...
i will have to see it with my own eyes to tell what was done wrong...
Title: Re: Clean out grounding design
Post by: robbietan on December 09, 2014, 04:33:45 PM
imagine several computers in remote places connected via a modem. a lightning strike at a nearby area and all the modems were busted. but only the modems, the computers are still functioning but are no longer communicating with each other.
Title: Re: Clean out grounding design
Post by: tony on December 09, 2014, 07:02:51 PM
again, unless i see it with my own eyes, whatever i say will only be speculation....
there is of course a reason, and grounding may not be the sole culprit...
Title: Re: Clean out grounding design
Post by: @badoy on December 13, 2014, 12:54:59 PM
unbonded systems tend to create ground loops which could damage systems.

ref ANSI J-STD-607-A
How??

As far as I know in industry and facility design the data grounding and electrical grounding are separate, considering minimum distances to each other to prevent noise interference and harmonics.
Title: Re: Clean out grounding design
Post by: tony on December 14, 2014, 11:42:58 AM
yes.....during commissioning of the grounding system,
both the dirty earth and instrument earths are tested for
continuity and insulation from one another,
we have to show the owners that the two systems are
distinctly separate.....
only then can we terminate the earths onto the ground pits...
Title: Re: Clean out grounding design
Post by: robbietan on December 15, 2014, 09:39:00 AM
How??

As far as I know in industry and facility design the data grounding and electrical grounding are separate, considering minimum distances to each other to prevent noise interference and harmonics.

they are separate with separate ground rods. however both are bonded at the transformer secondary to prevent uneven potential. with uneven potential, current tends to flow from the bigger potential and thus "ground loops"
Title: Re: Clean out grounding design
Post by: robbietan on December 15, 2014, 10:07:16 AM
(http://imageshack.com/a/img540/21/byPVkZ.jpg)
Title: Re: Clean out grounding design
Post by: tony on December 15, 2014, 12:09:24 PM
ground loops are created when there is a potential difference between two "ground points"
the rule being, a ground is zero volts....when this rule is violated, then you have ground loops...

there are design steps that can be taken, there are construction practices that avoids this...

if you work overeseas in an Oil and Gas refinery projects, then these things will be very clear to you....
Title: Re: Clean out grounding design
Post by: @badoy on December 16, 2014, 08:39:36 AM
they are separate with separate ground rods. however both are bonded at the transformer secondary to prevent uneven potential. with uneven potential, current tends to flow from the bigger potential and thus "ground loops"
ahh maybe that is the last resort to eliminate ground loops.....I guess if you get an uneven potential between two grounding pits maybe there is something wrong with the installation process, faulty workmanship and design systems.

AFAIK most of data centers & R&D facility here in Philippines don't accept these kind of grounding methodology. They requires separate grounding both for electrical and data. The two grounding pits were separated away each other with certain minimum distances.
Title: Re: Clean out grounding design
Post by: robbietan on December 16, 2014, 10:32:53 AM
ahh maybe that is the last resort to eliminate ground loops.....I guess if you get an uneven potential between two grounding pits maybe there is something wrong with the installation process, faulty workmanship and design systems.

AFAIK most of data centers & R&D facility here in Philippines don't accept these kind of grounding methodology. They requires separate grounding both for electrical and data. The two grounding pits were separated away each other with certain minimum distances.

kaya maraming nagpupunta sa amin kase ung mga workers ng electronics assempbly ei nakukuryente sa mga wrist straps nila. ayaw kase nilang i-bond ang data at electrical grounding
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 10:37:27 AM
Hehehe nagugulo dahil sa grounding.

Paano yung nagiging loose connection? Ano mangyayari?
Title: Re: Clean out grounding design
Post by: Super zHero on December 16, 2014, 10:54:51 AM
PLDT contractors, hindi na nagbabaon ng GND.  Umaasa na lang daw sila sa GND ng Meralco  ???
Title: Re: Clean out grounding design
Post by: tony on December 16, 2014, 11:12:47 AM
Hehehe nagugulo dahil sa grounding.

Paano yung nagiging loose connection? Ano mangyayari?


ibang issue yan...
ducter testing after torquing bolts and nuts on the copper busses are done to ensure low contact resistance...
https://www.google.com.ph/search?q=ducter+testing&oq=ducter+testing&aqs=chrome..69i57&sourceid=chrome&es_sm=93&ie=UTF-8

needless to say, loose bolts can cause fires, this happened to our low voltage vault room,
a dry type transformer ha a loose bolt...the fire that ensued, kept us awake for 72 hours
straight trying to repair the damage and restore operation...

our american boss was happy and he gave each one of us involved in the repair work a fat envelop...;)
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 11:29:34 AM
Sa single phase line multiground kapag nagloose ang return wire nabibigyan kami ng jolt(commonly bare in the provinces). At karaniwan din nakaearth ground . 
Title: Re: Clean out grounding design
Post by: tony on December 16, 2014, 11:32:01 AM
kaya maraming nagpupunta sa amin kase ung mga workers ng electronics assempbly ei nakukuryente sa mga wrist straps nila. ayaw kase nilang i-bond ang data at electrical grounding

wrist straps must connect to electrical earth as it is a safety issue....
again, unless i see the original design and looked at how it was implemented, then i will just be speculating...
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 11:39:19 AM
Is it same sir tony sa nabanggit ko sa last post ko kanina?
Title: Re: Clean out grounding design
Post by: tony on December 16, 2014, 11:39:21 AM
Sa single phase line multiground kapag nagloose ang return wire nabibigyan kami ng jolt(commonly bare in the provinces). At karaniwan din nakaearth ground . 

Is it same sir tony sa nabanggit ko sa last post ko kanina?

maybe you mean neutral return wires....
a ground wire is different from a neutral wire...

in a 3 phase system using the Y configuration,
the neutral is supposed to be zero volts, but in reality it can be something else...
that is why the neutral is earthed at the transformer side, so as to prevent roving neutral....
neutral and earthing must never be confused with one another...
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 11:52:39 AM
Ang alam ko lang kasi ay three phase with extra wire bare and commonly have the wire running down from the post to the ground rod. Hindi ko alam kung ano termination nila sa high side neto. 13.2kv.

So sa primary ng transformer yung hot side ay nakakabit sa isang phase line tapos the other is connected to the 4th wire that is the bared wired with wire running down a ground rod sa lupa.
Then sa secondary yung isang tap is 220Vac potential tapos yung isang terminal ay nakakabit sa 4th wire and also as return terminal sa 220-0 supply. Once magloose yung return wire nakakakuryente na yung return wire minsan that is usually a bare aluminum wire.
Title: Re: Clean out grounding design
Post by: tony on December 16, 2014, 12:03:53 PM
panisnin mo, merong ground runner yan...
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 12:14:16 PM
Ang common point dito sir tony is yung 4th wire ng high side, return wire ng secondary ay nakakonek rin sa ground rod katabi ng mga poste. So once magloose yung return wire sa entrada kapag hinawakan mo eh nangingiliti minsan which is usually a bare aluminum wire.
Title: Re: Clean out grounding design
Post by: tony on December 16, 2014, 12:19:39 PM
TBH, i am not too familiar with our local electrical codes...
but i had a good number of years working overseas as construction boy,
later on as QC engineer is Russia...
i am familiar with the Shell Standards, and the DEP....
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 12:32:09 PM
Minsan nga nakakalito. Lalo na't learning process pa rin ako. Iba rin sa 3 phase. Karaniwan ko nakikita is y-delta configuration where yung second terminal ng connection ng primary ay connected sa tatlong traffo bank then to traffo body and earth rod. Then sa secondary ay delta connection with three leads out lang walang ng neutral wire.

Meron din akong nakikitang parallel connection tapos ang metering ay 3 wire out, 1 wire is common.
Title: Re: Clean out grounding design
Post by: Super zHero on December 16, 2014, 12:48:30 PM
On the subject of wrist and foot straps, meron silang series resistor of something like 1meg for safety.  Para hindi makuryente.
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 16, 2014, 12:55:33 PM
1. Ok ba yan sir to damp static electricity with 1M value?

2. What about yung hawak ang meron leak from source line?

3. Paano naman yung loose sa gnd line na nakakonek sa electrical line grounding?

Title: Re: Clean out grounding design
Post by: Super zHero on December 16, 2014, 01:09:45 PM
The main purpose of a wrist or foot strap is to avoid the build-up of static electricity on a person's body.  A 1meg resistor is good enough to do the job.  On assembly lines or test benches, they are tested first or should be tested per ISO standards and requirements EVERY TIME they put on.

Any misuse or deviation from the safety standards is the wearer's risk.
Title: Re: Clean out grounding design
Post by: tony on December 16, 2014, 01:22:19 PM
static electricity is a real shocker....
i remember the many episodes in Russia wherein
i saw sparks jump from my hand to the brass doorknob, tickled me a lot,
sometimes with sounds too...;)
Title: Re: Clean out grounding design
Post by: @badoy on December 17, 2014, 09:06:14 AM
kaya maraming nagpupunta sa amin kase ung mga workers ng electronics assempbly ei nakukuryente sa mga wrist straps nila. ayaw kase nilang i-bond ang data at electrical grounding
It is evident that there is something wrong with the system design or workmanship issue. I already supervised one of the R&D company located at Ortigas Center (the company is based on Singapore) The building has two grounding provisions one for the data and one for the electrical but unfortunately after the series of testing conducted by group of Singaporean engineers the grounding system did not pass in their standards because of noise and interference. So, one of the solution is they installed separate grounding.

I guess loops will be prevented if the system is well design by the fully equipped engineers.
Title: Re: Clean out grounding design
Post by: @badoy on December 17, 2014, 09:08:19 AM
Ang common point dito sir tony is yung 4th wire ng high side, return wire ng secondary ay nakakonek rin sa ground rod katabi ng mga poste. So once magloose yung return wire sa entrada kapag hinawakan mo eh nangingiliti minsan which is usually a bare aluminum wire.
The only purpose of electrical grounding is to protect the human from equipment fault. Ngayun kung nakikiliti ka its time for you to troubleshoot the system dahil meron ka nang evidence of fault. makukuryente kalang kung meron nag-close loop from Line A, Line B & Line C going to equipment body. Hanapin mo yung sumayad na linya or baka nabasa.

Ground rods to ground rods cannot produce potential. It only absorb potential and if you noticed that there is an un-even potential between grounding pits then start doing maintenance works to your system to prevent loss of life and property.
Title: Re: Clean out grounding design
Post by: tony on December 17, 2014, 11:18:24 AM
IME, for power substations the individual earthing rod must measure 10 ohms or better,
and the earthing grid connected to lessbetter than 2 ohms....instrument earthing is even more stringent,
1 ohm or less and triangulation of rods are mandatory, this is how seriously earthing is implemented in such plants...
Title: Re: Clean out grounding design
Post by: Super zHero on December 17, 2014, 02:27:44 PM
A common mistake is making the "instrument" ground the same as the lightning rod ground.
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 17, 2014, 02:56:02 PM
Ganyan minsan kapag walang dalang gnd rod naghahanap sa paligid at kapag nakakita dun ilalagay.


Minsan sa tubo ng tubig. Kaya minsan naghuhugas ka ng kamay eh meron nangingiliti.
Title: Re: Clean out grounding design
Post by: Super zHero on December 17, 2014, 05:34:28 PM
// eh ako minsan pagnaliligo, meron nangingiliti  ;D
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 17, 2014, 05:47:40 PM
Siguro me shower heater ka sir Z?
Title: Re: Clean out grounding design
Post by: Super zHero on December 17, 2014, 05:57:25 PM
,,,,hindi, meron dalagita na pumapasok sa banyo  ::)
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:43:10 PM
PLDT contractors, hindi na nagbabaon ng GND.  Umaasa na lang daw sila sa GND ng Meralco  ???

puede yan altho may noise issues minsan. the best is for  a separate ground rod tapos naka bond sa meralco grounding system
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:45:01 PM
It is evident that there is something wrong with the system design or workmanship issue. I already supervised one of the R&D company located at Ortigas Center (the company is based on Singapore) The building has two grounding provisions one for the data and one for the electrical but unfortunately after the series of testing conducted by group of Singaporean engineers the grounding system did not pass in their standards because of noise and interference. So, one of the solution is they installed separate grounding.

I guess loops will be prevented if the system is well design by the fully equipped engineers.

maraming engineers kasi dito ang hindi pa ma experience on grounding and bonding issues.
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:47:59 PM
The only purpose of electrical grounding is to protect the human from equipment fault. Ngayun kung nakikiliti ka its time for you to troubleshoot the system dahil meron ka nang evidence of fault. makukuryente kalang kung meron nag-close loop from Line A, Line B & Line C going to equipment body. Hanapin mo yung sumayad na linya or baka nabasa.

Ground rods to ground rods cannot produce potential. It only absorb potential and if you noticed that there is an un-even potential between grounding pits then start doing maintenance works to your system to prevent loss of life and property.

kung may fault at hindi nag trip ang protective devices, its either mali ang design ng protection (not common) or mali ang design ng grounding (more common). marami kasi ang akala ei kapag nagbaon ka ng ground rod ei tapos na ang grounding.
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:49:47 PM
IME, for power substations the individual earthing rod must measure 10 ohms or better,
and the earthing grid connected to lessbetter than 2 ohms....instrument earthing is even more stringent,
1 ohm or less and triangulation of rods are mandatory, this is how seriously earthing is implemented in such plants...

5 ohms na ang standard ng meralco as many of their electronics need that level of resistance. hindi lang dapat sa substations, dapat sa lahat ng buildings ei ganyan ka stringent ang requirements
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:52:26 PM
A common mistake is making the "instrument" ground the same as the lightning rod ground.

na dapat ei bonded lang. lightning rods should at least be 2 separate rods, one each per building corner
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:55:03 PM
Ganyan minsan kapag walang dalang gnd rod naghahanap sa paligid at kapag nakakita dun ilalagay.


Minsan sa tubo ng tubig. Kaya minsan naghuhugas ka ng kamay eh meron nangingiliti.

ganyan kung masyadong mataas ang earth resistance or hindi maganda ang bonding ng grounded conductor sa tubo ng tubig.

assuming na metal ang tubo ng tubig at hindi plastic.... jejeje
Title: Re: Clean out grounding design
Post by: robbietan on December 18, 2014, 01:55:46 PM
// eh ako minsan pagnaliligo, meron nangingiliti  ;D

tsalap iyan
Title: Re: Clean out grounding design
Post by: kmb36td on December 18, 2014, 02:59:24 PM
less common yata ang static electricity sa pinas... because of the very high humidity... sa mga may snow at desert na country uso yun kasi dry ang air nila...... at saka di rin sila namamawis sa kamay di katulad natin...
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 18, 2014, 03:02:40 PM
Dahil sa mga damit nila siguro? at karaniwan yata sa kanila meron nakalatag na carpet sa sahig.
Title: Re: Clean out grounding design
Post by: motion55 on December 18, 2014, 03:46:14 PM
Dahil sa mga damit nila siguro? at karaniwan yata sa kanila meron nakalatag na carpet sa sahig.

Hindi siguro nilagyan ng Downy. Nakakabawas daw ng static electricity ang Downy.
Title: Re: Clean out grounding design
Post by: tony on December 18, 2014, 03:54:00 PM
5 ohms na ang standard ng meralco as many of their electronics need that level of resistance. hindi lang dapat sa substations, dapat sa lahat ng buildings ei ganyan ka stringent ang requirements

is that for the rod only or system?
the 10 ohm i quoted is for rod only buried into the ground and without anything connected to it...
in cases where the resistance is higher, then couplers are used to add length,
a rod usually measured 1.5 meters long and has a diameter of 16 mm,
i am not familiar with local practice though...
on one installation i worked on in Singapore, there were more than 500 rods all interconnected
using 120mm, 70 mm squared grounding wires....
Title: Re: Clean out grounding design
Post by: >>>^żżż^<<< on December 18, 2014, 04:20:51 PM
Ground rod pa lang  ulam na.


Satin electrical installation na, gusto magik pa.
Title: Re: Clean out grounding design
Post by: <<<<<------ on January 04, 2015, 11:45:39 PM
i wish i could post drawings and plans for grounding in the plants that i worked on...
yes, they are completely separate....but like i said, they meet at the ground where earth rods are buried for both dirty and clean earths in close proximity to one another....


usually ground separation distance is equal to the lenght of ground rod or ground matting surface area. make it twice to be safe.
Title: Re: Clean out grounding design
Post by: aldwin on May 27, 2015, 08:12:13 AM
,,,,hindi, meron dalagita na pumapasok sa banyo  ::)

bakit ngayon ko lang nabasa ito?    wahahahahahaha