Malibu (not) underwater transformer

I have a Malibu 12V transformer/timer I use for regular outdoor lighting. Works fine. I recently installed a pond, and would like to attach some submerged 12V lights to the transformer. However, I notice a sticker on the transformer stating "Not for connecting to underwater lights". At the Intermatic (Malibu) site, it states in the instructions for my transformer that it doesn't have a "ground shield" and thus is not designed for working with submerged lights.
Question: Anyone know what this "ground shield" is? If I connect it to a GFCI outlet, will I be safe to use it anyway, underwater, or will my fish (and I) fry?
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Might go buy a pool light transformer, usually 300 watts & cheap enough. 120/12v
Shield completely isolates Hv from Lv windings - grounded sheet metal plate between Hv/Lv windings - Malibu winding short on either side the A/C will/could juice up the lv and kill your fish and the neighbors kid due to whatever,,, hungry bugs, rust, lightning, defective varnish, fertilizer burn, chemical corrosion, wives driving abilities, etc.

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It should trip the GFCI if that happened but the code still says to use a listed transformer.
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Maybe the newer GFCI are better but from failures I have seen around my place, I have come to consider a GFCI as "belt and suspenders" rather than the primary safety device.
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Yes they are. The U/L standard was upgraded last year.
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snipped-for-privacy@aol.com (Greg) wrote in message

Hmm, still stumped here. I know I could just buy a new, grounded one, but something just doesn't seem right here.
If the non-grounded, non-shielded 12 volt transformer I now own is such a hazard, and if there is a short with it, then how is that any different from the other 120V submersible devices currently in my pond, which are not grounded at all? I'm referring to the pump, as well as a low-water shutoff switch. Both have no third grounding prong, and are only protected by the GFI.
Of course I want to do the work to code, but there doesn't seem to be any rhyme or reason to it here...
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If you have a GFCI on it I don't really see a huge danger. This is a fish pond, not a spa or pool you will be swimming in.
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Your 120v pump and low-flow cutofff are UL listed as "submersible" and designed and built to operate safely under water. It has nothing to do with the fact that they're grounded or not grounded.
Underwater low-voltage lights are designed and built with NO protection between the exposed low voltage electrics and the water, and because of this, require a transformer which, amongst other things, does have a grounded metal shield between the primary and secondary windings of the transformer.
If the shield was not present, in the unlikely event of transformer meltdown, there exists a slight possibility that the line voltage windings on the transformer core could liven the core to 120 volts, and in turn pass that 120 volts right into the low voltage winding and into the pond water, right through the water via the non-watertight terminals of the submersible lights and oftentimes, submersed splices.
BTW, most outdoor L.V. transformers 300 watts - 600 watts are only available in the better, shielded/grounded versions. It is only the 88-180 watt cheep-o's that come in both varieties because, it's probably a dime cheaper to make the more common, less safe variety that's included with every piece of crap plastic landscape lighting kit.
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