Earthing Strip /Wire / Pit Quick Reference-(Part-1)
September 5, 2013 21 Comments
Transformer-Earthing Wire / Strip Size:
|
Size of T.C or DG |
Body Earthing |
Neutral Earthing |
| <315 KVA | 25×3 mm Cu / 40×6 mm GI Strip | 25×3 mm Cu Strip |
| 315 KVA to 500 KVA | 25×3 mm Cu / 40×6 mm GI Strip | 25×3 mm Cu Strip |
| 500 KVA to 750 KVA | 25×3 mm Cu / 40×6 mm GI Strip | 40×3 mm Cu Strip |
| 750 KVA to 1000 KVA | 25×3 mm Cu / 40×6 mm GI Strip | 50×3 mm Cu Strip |
Motor- Earthing Wire / Strip Size:
|
Size of Motor |
Body Earthing |
|
< 5.5 KW |
85 SWG GI Wire |
|
5.5 KW to 22 KW |
25×6 mm GI Strip |
|
22 KW to 55 KW |
40×6 mm GI Strip |
|
>55 KW |
50×6 mm GI Strip |
Panel- Earthing Wire / Strip Size:
|
Type of Panel |
Body Earthing |
|
Lighting & Local Panel |
25×6 mm GI Strip |
|
Control & Relay Panel |
25×6 mm GI Strip |
|
D.G & Exciter Panel |
50×6 mm GI Strip |
|
D.G & T/C Neutral |
50×6 mm Cu Strip |
Electrical Equipment Earthing:
|
Equipment |
Body Earthing |
|
LA (5KA,9KA) |
25×3 mm Cu Strip |
|
HT Switchgear |
50×6 mm GI Strip |
|
Structure |
50×6 mm GI Strip |
|
Cable Tray |
50×6 mm GI Strip |
|
Fence / Rail Gate |
50×6 mm GI Strip |
Earthing Wire (As per BS 7671)
|
Cross Section Area of Phase, Neutral Conductor(S) mm2 |
Minimum Cross Section area of Earthing Conductor (mm2) |
|
S<=16 |
S (Not less than 2.5 mm2) |
|
16<S<=35 |
16 |
|
S>35 |
S/2 |
Earthing Resistance value:
|
Earthing Resistance Value |
|
| Power Station | 0.5 Ω |
| Sub Station Major | 1.0 Ω |
| Sub Station Minor | 2.0 Ω |
| Distribution Transformer | 5.0 Ω |
| Transmission Line | 10 Ω |
| Single Isolate Earth Pit | 5.0 Ω |
| Earthing Grid | 0.5 Ω |
| As per NEC Earthing Resistance should be <5.0 Ω | |
JIGNESH PARMAR
Dear sir/madam l had received electrical thump rules 4,5,6. so i want electrical thump rules 1,2,3. so plase kindly send me. thankyou M.SIVA
Is is already given in the Blog !!!!
Thank you for the valuable notes.
Dear Sir,
Thanks for valuable info.Kindly send me SLD of PCC in LT panel…….
Sir .. Thank u for the Valuable information.. Can u pls upload details of Panel fabrication.
dear sir .
the thumb rule of electrical note is very help full
thankx so much RESPECTED SIR
to share ur lot of experience with us
Thank you so much for the very interesting information.More power and God Bless.Can you give me information on how to calculate cables size current capacity in meters.
Regards, Angelito
Sir Thanks alot for Shairing Such a Very very helpful Informative… ALLAH bless you… and keep on sir… Once again Thanks
Hi!Sir.Hope you are doing good.I’m very much thankful to you for this kind information regarding Electrical system. My question to you is my transformer is 315KVA so, what should be the size of the HT Cable.And also please let me know that how to select the HT cable?
Thanks & Regards
Shahbaz Hussain.
Sir
We have a cold storage with all the electrical load @ 197 hp.
Right now we have a 185 Sq.mm cable from the transformer to the panel.
When we are operating at full load the 185Sq.mm cable is heating up & mains are getting burnt out. Can you suggest suitable cable, & mains size.
Dear Sir,
how we calculate earthing strip size and wire size for ESD (electrostatic discharge) and EPA (earth protection area) in electronics assembly line. We are using ESD mat, ESd tile to discharge electrostatic charge.
in two same capacity dg synchronization, what should be the rating of between 2 dg bus coupler,.
is same of single dg or double of that.
contactor voltage is ac or dc in contactor coil section as you indicated suffix
Dear Sir,
It will be helpful if you will share reference standard for earth conductor size for motors.
How are You..sir….I am very much impressed with your notes on electrical ….
Kindly send me a total date in pdf format for my reference
Eamil Id : anilkumar_33@rediffmail.com
Ph: 9491392855,9441063197
I will be much thank full to you if your provide the same.
With regard
Anil Kumar Patel,
Manager Marketing -Cables & Conductor
Polywires & Metal Industry,
Hyderabad.
sir,
how to derive body earthing conductor size for 4000A incomer power panel.
Hi Sir,
i need one help.
how to select motor body earthing sizing of motor.
how to calculate earth strip when there are 500 person on floor and avg static volate is 500V
How much resistance per unit gi and copper stip.
Dear Sir
Thank you for the detailed information. Please also give us the single core Musltistranded aluminium conductor equivalant to cross sectional area of the GI earthing conductor.