This has been discussed in the past, here https://community.victronenergy.com/questions/27100/isolation-transformer-earth-connection.html
If I’m reading this correctly, this is only useful for metal hull vessels. If so, why on earth (pardon the pun) doesn’t the manual say that? There is no benefit I know if to connecting shore and boat ground while ashore for FRP vessels, and doing so is an invitation for forgetting to remove the jumper when relaunching.
Perhaps more importantly, even a metal hull, or metal underwater fittings, have no reference to the primary/input power, so even if the hull or a metal fitting became energized with secondary/output power, someone standing on the ground could not be shocked by it, for the same reason a bird can stand on a wire carrying thousands of volts and not be shocked. The secondary of a transformer behaves like a power source, all faults return to the source, with no reference to the “dirt” under the vessel. So, I remain confused by this ‘shore’ grounding guidance.
A few other questions/comments on this transformer…https://www.victronenergy.com/upload/documents/Isolation_Transformer_3600W_Auto/108939-Isolation_transformers-pdf-en.pdf
- It has a fixed 1:1.05 boost, so if used with 240 VAC, it boosts to 252, which is higher than normal. It seems this transformer is really designed for use with 230 VAC, which it boosts to 242?
- It can accept 120 or 240 primary, and passes that voltage through, with the aforementioned boost, but it cannot provide split phase aboard, so for 60 Hz/N. Am use, it’s essentially limited to 120 primary and secondary, 30 amps, unless you use an auto transformer after the secondary?
- The installation manual shows a shield. As far as I know, no toroidal transformers have shields, but this one does? It also shows the shield grounded on the vessel and chassis grounded to shore, the inverse of the ABYC E-11 standard.