devices in play:
Quattro 48/5000 … (UL),
AC In-1: old Northern Lights 5Kw M643 Generator
AC In-2: Isolation Transformer 3600W Auto 115/230V supplying 30A/120v shore power
I have the Isolation Transformer’s j21/j33 jumpers connected to create an N-E bond.
My question: will the Isolation Transformer provide the N-E bond to the system even when there is no shore power (and therefore the Isolation Transformer has no power)? including when the quattro is in inverter mode and also when the generator is running?
No, since the bridge is on the AC input side, so as long as the respective ACin is disabled/switched off, N-PE bond will not be provided by that source.
Then the N-PE bond is provided by the Quattros internal N-PE relay.
Then the N-PE bond is provided by the generator.
If you want a permanent N-PE bond then you have to add that on the ACout, disable the internal N-PE relay of the Quattro, as well as remove the N-PE bond on both isolation transformer and generator.
Since you mention UL and 120V i guess you are in the US? Best to check with your local regulations.
For example, here in central europe, in the above situation with a fixed N-PE bond on the ACout, i would be prohibited to run the generator without switching its ACin for extended periods of time, since its output would not be bonded to earth. I think Australia has similar rules, since theres special AUS gridcodes with “Neutral path externally joined”
@chrigu - thank you for your quick reply, and yes, this a US based implementation, i should have noted that, thank you for pointing out that out!
it seems a reasonable test would be to check for continuity between the output neutral and ground while the Isolation Transformer is not energized by shore power. My results when performing this check is continuity (beep) when the jumpers are in place and when the jumpers are removed there is no longer any continuity. fwiw the output wires are disconnected so there are no confusing downstream connections. These results would indicate the bond remains even when the unit is powered off. given that the continuity is found at the output terminals, and these terminals remain connected to the system, this would seem to supply a continuous N-E bond to the system at all times.
With unit you mean the Quattro here? I dont know if you are using a Quattro 1 or Quattro 2 (or Quattro-II) but they are both very similar when it comes to how the ACins are switched through.
Both input relays are double pole, switching both L and N. Now if the Quattro is switched off, then i would expect no onnection between N and PE on the ACout. In any other situation, there would be an N-PE bond, either from the Quattro itself or from one of the inputs. And with just measuring resistance you have no way of telling which one you are measuring
I am really only speaking of the Isolation Transformer and its bonding. Jumping j21/j33 in the IT creates an N-E bond, and there are lots of information on that working when shore power is connected to it. however, i am trying to find out if that N-E bond remains even when there is no shore power connected. the continuity tests seems to indicate the N-E bond continues to exist.
The Quattro is downstream of the IT and its ground relay setting will definitely come into play depending on the answer to the above question.
Again, thank you for your response and I apologize for any confusion.
I did come to a realization with the help of your response; it does not matter if the N-E bond is permanent within the Iso Transformer, as the quattro would be cutting both the L and N (as you noted) to the IT, thereby eliminating it as a bonding source. thanks again!
