ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (CoolWill), 250 guests, and 13 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 2 of 2 1 2
#142460 01/22/05 01:59 PM
Joined: Aug 2001
Posts: 7,520
P
Member
I can see no advantage to separating the gen-set earth from the building earth either, in fact I can see several problems with such an arrangement.

I'm thinking along the lines of switching transients as that 4-pole transfer switch is operated. I've run across RCD-tripping problems on just a single-phase system where there was a little earth leakage (from heating elements) and a double-pole isolator had the line side closing a fraction of second before the neutral.

The varying loads on the system at different times could account for why it trips on some changeovers and not others. It could also be dependent upon the point in the A.C. cycle at which the contacts close.

#142461 01/22/05 05:06 PM
Joined: Apr 2001
Posts: 518
J
Member
Let this Yank take a wild guess or two...

Assuming that your rcd's trip at a low level, say 30ma, it mould resemble a problem I had with a UPS system once; in that case, there was a connection between the utility neutral and the back-up system neutral that shouldn't have been there.

Paul, you may also be on to something...if the generator is diesel, and has a heater in the fuel tank, and that continues to be powered by the utility while the generator is operating, this sort of problem might come up.

Failing these ideas, are we sure that the transfer switch is operating properly- or is the system getting a little crossover power for an instant during the transfer?

Just some thoughts.

#142462 06/10/05 03:06 AM
Joined: Jun 2005
Posts: 17
R
Member
Hmm this one could be a dinger -

you say that you sell power back to the grid so you will have some form of syncronisation working in there, this could set up some form of imbalance on the lines to trip the RCD.

How ever Im thinking on the lines of the genset neutral earthing if it has this fitted - this will cause some problems with the rcd's worthy of some investigations....

Rugged

#142463 06/10/05 03:48 AM
Joined: Jul 2002
Posts: 8,443
Likes: 3
Member
Ruggedscotty,
Now there is a username that just screams of hard work!. [Linked Image]
Welcome to ECN, mate.
Great to have you along. [Linked Image]

#142464 06/10/05 07:18 AM
Joined: Mar 2005
Posts: 1,803
Member
Yet another Scotty for the wallchart!
Alan


Wood work but can't!
#142465 06/10/05 12:34 PM
Joined: Jun 2005
Posts: 17
R
Member
thanks for the welcome - Im looking forward to contributing more.....

If you want to ask me anything feel free - Im based in scotland work for a large company here and Im in the building management side of things.....

Rugged

#142466 06/12/05 05:35 AM
Joined: Aug 2001
Posts: 7,520
P
Member
Welcome aboard Rugged. ECN has quite a few members from north of the border now. We sassenachs had better watch out! [Linked Image]

#142467 06/13/05 09:56 PM
Joined: Jul 2002
Posts: 8,443
Likes: 3
Member
Alan,
Quote
Yet another Scotty for the wallchart!
You've got a wall chart?.
That's actually quite funny, in a creepy stalker sort of a way!. [Linked Image]

Page 2 of 2 1 2

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5