Norms for Neutral Earthing of Diesel Generator

A little specificity please; gen type, load, location-that kind of stuff.

heres a thought if you hold onto the live wire of a generating set you wont get an electric shock as there is no return circuit.

but if you earth it there would be a return path and sizzle.

correct

Sorry..........THe DG is of rating 750KVA.....used to feed hydro jetting(high pressure cleaning) which has motor in it.

Single or 3 phase, rather an important point which you consistently overlook......

You are not the right person to question safety regs.. Sorry.

BVut you simply do not know enough.....

I think it was some common sense that the 750KVA DG will have a 3 phase load!!! I already mentioned that the load is single.If I was wrong I take this opportunity to convey that the DG & load is 3 phase.

Then you need a ground to neutral SAFETY link......

If there was no connection made, then a short to ground might not blow fuses, it might just kill people who touch it bthough! (To kill a human only a small current is required!)

For a fuse (or CB) to "blow", you need a proper fault current path. The link provides that path.

Its not perfect though (as many here know!) and ELCBs are also recommended....

Strangely they are not required by law here here in Germany, except for new build houses.....crazy!! But my 100 year old house has had them (three phases) for years.....!! Up to now I have not accidently tested them. I did do that once at the office though, OUCH!!! I do NOT recommend that method....

Depending on the generator, you might have a floating or not. Generator's of all sizs form 1kW to 100kW + now have a ground terminal for a ground conductor to be terminated to the generator. If it does not, please consuilt the supplier/renter/manufacture of generator for proper grounding points.

The best way is to dig a hole and install a ground plate (any supplier has this in stock) and have it min 6' below grade. If you don't want to dig and soil provides for it, install grounding rod (10') copper using proper installation tool. Conductor size should fallow electrcial code in area.

But for a main breaker of 200A 120Vp-g.... I would suggest #3awg or greater.

Hope this helps, and if anyone else can correct me, feel free.

how do you know which wire is neutral on single phase portable generator 2kva output

If you are fortunate... with the genset NOT running, test resistance of each conductor to the frame. I'd say "should" but "possibly" is better, one may read low resistance around 0.5 Ohm, and the other may read high resistance around 500 Ohm. Low resistance = neutral.

You have to earth the neutral of the D.G set even if its a temporary or permanent. By temporary it means that the set will be used as a stop gap arrangement till the capital equipment is installed might be to meet the construction activities or to deliver power during power failures or black outs . Mind it during the construction stage there will be severe load un balance due to a number of welding transformers, cutting & bending machines, pumps for water supply & also for dewatering activities apart from lighting during nights. Each contractor will draw loads from the D.G set & the load distribution may not be well distributed in each phase . Therefore there is every possibility of Neutral being getting unbalanced. Under these circumstances its essential that the DG set neutral is earthed properly. Whether its temporary or permanent it has to function by delivering the electrical power so its imperative that the neutral is earthed.

Can someone define D.G. for me? I am unfamiliar with this.

D.G Set means DIESEL GENERATOR SET.

Any generator that is used for any supply to domestic or industrial use must have it's neutral earthed if there are earth leakage circuit breakers installed: These will not operate otherwise!

For very short temporary usage, you can get away with the need(Few hours per day, or really very well controlled area...but not advisable for long periods and not restricted area).

It's the difference between a TT earthing arrangement and an IT earthing arrangement. Check out the article in Wikipedia for a more detailed explanation.

Its quite simple really, (I assume USA and a 3 phase generator), if you want to use 120 VAC for anything, you need a neutral to phase connection. Not linking the neutral to earth could mean full phase voltage on any metal frames in the event of some sort of failure....

Its far safer to link the two.....notice I did not say "safe".....just safer....ELCBs will make it even safer......

The earth you need is a 3 wire cable (single phase), neutral, earth and phase.

The earth wire must make good contact with th earth pin on any device you connect so that it's frame is at the same potential as the earth wire.

The 3 pin socket on your generator, should be so organised that there is a link between earth and neutral at the generator, so that if an earth to phase fault occurs, a fuse or breaker is blown.

An ELCB or similar added provided even more protection at much lower amps....

So you really need both, over current and earth leakage protection.

Its similar with 3 phase too.....

You could drive a spike into the ground so that the generator does not "float" too much, but unless the earth is really wet and or you drive it several meters into the ground where the soil is still wet, (and test with the right equipment for valisity) I personally cannot see much of a gain in safety......but the ELCB is then even more important than before - if possible!!

ELCBs sometimes have a bad reputation of going off with no failure. My experience is the opposite, if one trips (assuming it is correctly installed) something is WRONG!!! It just takes time and knowledge to find out what!!!

Dear Mr.giri,

Whether it temporary or permanant installation, Neutral Earthing is COMPULSORILY to be proided from Safety Point of View,.

DHAYANANDHAN.S

If in doubt, consult a local qualified Electrician.