Many times we ask question, can improper earthing slowdown my network ? or improper earthing can cause my PC to hang or restart ?
Yes, definitely yes. in fact it can cause - much more damage to equipment. In india we call it Earthing in US they call it grounding.
Improper earthing plays a great havoc as far as IT (for that matter any electronics) equipments are concerned. But IT support staff pays very less importance to earthing. In fact, improper earthing can cause very erratic behaviour in electronic equipments: like:
- PC hangs or restarts abruptly.
- Hard disk crashes before its life.
- Network equipment hangs or slows down. this is biggest problem and hardest to detect.
- And finally, you get an electrical shock
Now, the problem is that this is very difficult to troubleshoot logically. hence Support Engineers spent lots of their time trying to do various gimmick, but problem prevails or pops up after some time.
In this article we try to understand following points:
- How electricity works
- Why Earthing is required ? What is th problem.
- How earthing works.
- What is effect on networking equipments (or any electronic equipment)
- How to measure if earthing is proper (within limits or not)
- When earthing is not required ?
- Installing & Maintaining Earthing
How Electricity works:
- To complete an electrical circuit and to make things work, we need a full ring of electrical conductors.
- Normally this is a live wire in the cable from the generator (power station) to the plug socket in the home, through the equipment (for example, the PC),
- And then Back through the neutral wire in the cable to the generator again.
Where is the problem?
- BUT, if some metal part gets in touch with phase wire, there is a leakage.
- Electricity has a problem, it follows shortest route. (Jidhar Bojha Udhar Soja)
- Now, when you touch any part - Elec gets a shorter path to earth - and i.e. YOU & earth.
- Remember our body and mud also conducts electricity ! !
- Even when there is no metal part touching phase, still we need earthing because neutral wires in India are not always perfect.
How Earthing works :
- So, we put another copper wire, called earthing wire.
- Since copper is better conductor of electricity than our body - electricity will flow from there and not our body (remember jidhar bojha udhar soja)
What is effect on networking equipments (or any electronic equipment)
- Data is transferred as electric waves, which due to earthing this gets distorted.
- Improper grounding causes NOISE in lan.
- More speed means more data in shorter cycles, Which is more prone to effect. (so 1 gbps can have more problem than 100 mbps)
- With Low voltage devices, this problem increases.
- The problem is worsened when the protocol is udp and not tcpip
- Many cisco equipments have grounding LUG (special connector provided by Cisco)
How to measure if earthing is proper (within limits or not)
- Generally in there are three pin plugs. - Phase, Neutral & Earth
- Phase - bottom right -
- Neutral - bottom left.
- Earthing - Top
- Checking Earthing - method 1 (old way)
- Get a 100 watts bulb.
- Now put one wire into phase and other in neutral, and check whether it glows or not. (not the intensity of light)
- Now put one wire into phase and other in Earthing, and check whether it glows or not. (not the intensity of light)
- Compare both intensity, if its same - it means earthing is proper.
- Checking Earthing - method 2 (new way)
- Use multimeter - set it of 750V AC
- Check Phase + Neutral - (generally it should show 220 V in India)
- Now check Phase + Earthing (note the readings - it should be +/- 5V as compared to reading no. 1) e.g.: 227
- Now check Earthing + Neutral (best is 2 or below, but it should be near 5V) - e.g.: 8
- Total leakage is : (B-A) + C = (227-220) + 8 = 15
- What is bearable earthing leakage, that can be tolerated ?
- Where as it depends on the instrument (and its sensitivity), but generally in case of IT equipments it should be less than 15. (desirable is less than 3)
When earthing is not required ?
- When no metal parts in entire equipment - that user can touch
- When equipment is double insulated. (two layers of protection)
Installing & Maintaining Earthing:
- A copper plate is installed with lots of Salt + Coal, 5 to 7 feet under ground.
- Care is taken to keep this place little damp with moisture.
- Combination of Salt + Coal + Moisture, makes it very good conductor of electricity.
- However, this same thing also causes corrosion.
- GI or copper (wire, plate or connectors) attracts corrosion after some time, its usually 7 years, but in cities like Vapi - its half life.
- Now there is new technology called Chemical Earthing, where this corrosion is avoided - but its costly.
Tips for Support team
- Before initiating, investigation get electrical reading in following format:
- Phase + Neutral =
- Phase + Earthing =
- Neutral + Earthing =
- I suggest that every support case sheet, should have these reading to be taken compulsorily.
- Dont trust on your hands, If you are not getting it means there is no earthing leakage - can be a very misleading myth.
I hope this article is useful for everyone in the IT Field, I request and welcome your suggestions and comments on this article.
