Installation of a 25KVA DG set

is this for total connected load plus 1.5 time of switching on maxium rated load ?

is this with canopy.

Diesel fule ?

The type & lay out of your house ?

With Auto Tap Change Switch ?

Usually make sure that only One source is connected i.e with electrical and mechanical inter lcok.

Pipe type earthi with 2 nos eath conductor each to neutral for solidly earth and 2 nos to body earth

Get licenced eelctrical contractor to make the schematci drgs approved by statutory authority prior to commencing of utilization od DG Power.

nascon

The House is three storied house in Vasant Vihar, New Delhi. I have installed the DG set for the first floor that I own. We require the DG set when normal power goes out. We require it for running 3 to 4 Air Conditioners and two Deep Freeze units.

The DG set is installed on the roof. The earth pit has been made in the back lane. The contractor has dug 4 holes in which he has inserted tubes with a hole. The earth is connected through galvanized strips and then through a thimble to the main earthing cable. The supply is 3 phase but the DG set has a single phase alternator that supplies power to all phases through an interlock. I do not understand all the terms.

Kindly send me a diagram to show what I need to actually do and what are the provisions in the IS Code on this matter.

Fuel used is Diesel.

What do you mean by " Usually make sure that only One source is connected i.e with electrical and mechanical inter lcok."

Which is the staturoy authority in Delhi on this subject?

If you give me the Tel. No. or address in New Delhi of Nascon I will contact you for full details and help I require.

Thanks

R.Gupta

?????The supply is 3 phase but the DG set has a single phase alternator that supplies power to all phases through an interlock???????

do you have three phase load, i.e. 3phase deep freeze ???????

If you have ........then dont use the DG you will burn the compressor!!!!!!!!!!!!

I think that what he means is that although the country supplies 3 phase to houses, houses themselves (like in the UK) only get a single phase from the street. The DG being interlocked so that it cannot "back feed" the supply.....

It appears that things have been done correctly at least, but to somehow rely on CR4 as the final "Checker Upper" is strange to say the least!!

What you need is a local fully qualified Electrical Engineer that does not have any contact to the installing firm, to come and at your cost, give the complete installation a good checking over.

In some countries you can pay for the Engineer to come from the Electricity board and give a certificate. Not for free of course, but well worth the investment!! Germany does it this way....

It is mandatory requirement of the company or engineer who installed the DG set to provide the necessary earthing as per IE rules and IS specification. If he has not done it you must insist on him to do it. As for mechanical and electrical interlock it must be ensured that while the mains are on the generator supply cannot be switched on to your wiring and the change over should be done only when main supply is off. This interlock is mandatory for safety reasons and has to be done with the help of suitable Manual or Automatic change over system. As for the size of cable use the same size of cable used for mains connection or a cable as that will cover the actual capacity requirement of full connected load .

Does this have an automatic start / stop panel that will switch on the unit automatically if the power fails? If yes, then you need an automatic transfer switch. http://www.ascopower.com/cgi-bin/redirect.pl?/main.htm Click on automatic transfer switches, then click series 165 where you will find the automatic version or a manual version. The caution of mechanical interlock is a caution to not have the mains supply from normal power connected at any time to the generator. The switch above will do that. You need one common switch designed for this purpose so at no time can the mains and the generator be supplying the building at the same time or it will destroy your generator and may cause a fire.

Some practical things for backup power generators:

1) The diesel smoke may recirculate into other buildings; take care for smoke discharge path

2) Fuel leak on the roof may be a fire disaster; think about what will happen if the fuel leaks 20 liters on the roof.

3) Vibration may upset the top floor people. Use spring mountings. In severe cases, I've filled the base frame with concrete and placed the heavy block on springs to dampen vibration from the roof.

4) Engine mechanical noise will exceed the exhaust noise.

5) Check for de-rating for your altitude and temperature. 25 kVA is a sea level rating and probably at 25* C. And also it may be the 'emergency (standby)' rating where they expect you to only run it for one hour a day or per week. Ask the supplier if the rating is 'standby' or 'continuous' duty. There will be 20% difference. So if your building is 20 kVA load and you have a 25kVA standby rated set, and you expect to run this unit for 3-4 hours a day, or 10 hours a week, it will not perform as long as a unit rated 25 kVA 'continuous duty', which will have a larger engine and larger alternator.

6) Unfortunately, if you have this many questions, then it is clear you do not have a knowledgeable contractor installing this. If you or your contractor does not have several years experience installing exactly these systems, there exists a great risk for personal injury since these systems can cause fires if not properly installed. And the fire may come when the machine is operating meaning no power in the streets or building to see to get out. You have harm residents in the entire building. You are fixing one problem but making about 10 huge safety risks for yourself that do not exist before you installed this. Take care.

Indeed Good reply Petro Power!

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