been blocked by every electrician as far as article 250 is concerned
been blocked by every electrician as far as article 250 is concerned
(OP)
ok i currently have a system consisting of a 10kva single phase 3 wire 0/0/N-G bonded generator connected to a 16KVA 2 wire 0/0/G connected to a multi-tap isometric transformer to convert 2 wire 240 (0/0/G) to 230 (O/N/G). Now this system is mobile (trailerized) and the generator does not carry a neutral wire (so it is directly connected to ground) and the transformer is also Neutral/Ground Bonded. this system is hooked up to energize a communications antenna with a small computer network system. any thoughts on this??? any critism or suggestions would be great. if you want to quote the NFPA 70 then please add the article and paragraph please. i have an idea on what i need to do but i would like to know what should have been done from a more removed/unbiased perspective.
thanks
drknexus02
thanks
drknexus02






RE: been blocked by every electrician as far as article 250 is concerned
David Castor
www.cvoes.com
RE: been blocked by every electrician as far as article 250 is concerned
cleverson
RE: been blocked by every electrician as far as article 250 is concerned
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: been blocked by every electrician as far as article 250 is concerned
RE: been blocked by every electrician as far as article 250 is concerned
Isometric transformer
single phase 3 wire 0/0/N-G bonded generator ................. the generator does not carry a neutral wire (so it is directly connected to ground)
0/0/N-G bonded generator
0/0/G
240 (0/0/G) to 230 (O/N/G).
Why 230 Volts?
Where in the world are you? Are you working to a British or European standard?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: been blocked by every electrician as far as article 250 is concerned
RE: been blocked by every electrician as far as article 250 is concerned
It may be more informative if you gave yopur requirements in a different format.
Try something like 120/N/120, or the British standard, 240/120/N
Converting betwqeen the standards requires defining a different wire as the neutral and moving the ground connection to the newly defined wire. I encountered this issue with a number of single phase gensts from GB. The first one threw me, but after knowing the issue the alterations were quick and simple. I contacted the supplier and future sets were supplied with the appropriate connections.
If you are powering standard North American equipment, reconfigure your generator, loose the transformer, and carry the neutral to your panel.
The generator neutral should be grounded to the generator and trailer frame with one connection only between the neutral and ground.
THE TRAILER MUST BE PROTECTED BY AUXILLIARY GROUND RODS OR A GROUND GRID. Often there will be an existing ground grid to which the trailer frame may be connected.
If your equipment is other than 115V, 120V, 115:230V, 120:240V, 230V or 240V. Let us know and we will take it from there.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: been blocked by every electrician as far as article 250 is concerned
RE: been blocked by every electrician as far as article 250 is concerned
RE: been blocked by every electrician as far as article 250 is concerned
Your incoming power system (UPS and transformer primary) doesn't seem to require a neutral so you don't need to feed one from the genset or from utility.
You have a transformer that takes 240V input and produces 240V output with one leg being called the neutral and grounded? This isn't a typical North American power source but if that is what your equipment requires then that's what you need. This neutral is seperate from the primary side neutral (or no neutral) and would not get connected back to the genset or the utility. Seems to me you would bond this neutral to ground at the service panel in the trailer and ground the trailer.
RE: been blocked by every electrician as far as article 250 is concerned
RE: been blocked by every electrician as far as article 250 is concerned
What utility is supplying your grid power?
Your nomenclature is confusing some of us who probably have a combineed total of a few hundred years experience.
LOSE THE 0/N/G. It is nonstandard and ambiguous.
Tell us your voltages from
Line to line. L1 to L2 if aplicable.
Line to neutral. L1 to N, L2 to N if applicable.
Tell us which conductor, L1, L2, or N is grounded.
Buy (North) American
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: been blocked by every electrician as far as article 250 is concerned
jghrist - I think you meant 277V line to neutral (from a 480V/277V system). 208V is typically the phase to phase voltage of a 3-phase 208V/120V system.
RE: been blocked by every electrician as far as article 250 is concerned