Exposed bus bars in a low voltage cabinet?

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johno1234

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#324987 22-Jun-2026 21:25

Hi all,

i inherited a system of garden and landscaping lights in our house. The wiring is both 12VDC on the PIRs and some lights but 24VDC on most lights. All the wiring leads back to a cabinet in the basement with has two DC power supplies and a relay driven by the PIRs. It’s a bit messy with wire connectors all over the place. Am thinking about installing 24V, 12V and common screw terminal bus bars. Is it acceptable practice to have exposed low voltage bus bars? There is no exposed mains power. The power supplies are plugged into a double power socket.

MikeAqua

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#3505376 23-Jun-2026 09:51

Safe uncovered but it's better to cover them. Not to avoid injury as much as to avoid someone causing a short circuit with a tool or whatever.

If you head to JayCar, Burnsco, Marine Deals or Smart Marine sites, and find busbars designed for DC low voltage systems that come with a clear plastic cover. Marine stuff is spendy ... a cheap 6-way covered busbar will cost ~$35. But it will be nickel plated and won't corrode. Pair that with some ring terminals and heat shrink, and it will last for a very long time.

A cheap option is to go with something like this brass busbar and leave it uncovered. Or if you have a set of taps, you could make your own from a copper bar.

Mike

johno1234

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#3505388 23-Jun-2026 10:15

Plan to use bootlace ferrules and screw terminals as the dc garden cable is 4mm2 with stray strands wanting to go everywhere.

gzt

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#3505392 23-Jun-2026 10:32

You'll want to add a fuse for sure

richms

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#3505428 23-Jun-2026 12:18

You mean extra low voltage.

I have done similar but its all 12v from some dell server power supplies.

I got some car fuse blocks that have 6 blade fuses, and also 6 negative terminals available on it.

The PSU can do 1200W, so 100A available so fuses were a must for the small stuff going out to the lights.

Richard rich.ms

MikeAqua

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#3505454 23-Jun-2026 13:41

johno1234:

Plan to use bootlace ferrules and screw terminals as the dc garden cable is 4mm2 with stray strands wanting to go everywhere.

That brass screw-terminal busbar I linked to would work fine with ferrules.

Mike

johno1234

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#3505625 23-Jun-2026 19:29

MikeAqua:

johno1234:

Plan to use bootlace ferrules and screw terminals as the dc garden cable is 4mm2 with stray strands wanting to go everywhere.

That brass screw-terminal busbar I linked to would work fine with ferrules.

Yep that’s the form factor I’m using. Not shielded but in an enclosure so I’m OK with it.

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johno1234

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#3506021 25-Jun-2026 14:07

Ordered some bus bars and a buck converter from Amazon on Tue afternoon, arrived today Thu. How can they do it?

richms

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#3506024 25-Jun-2026 14:31

johno1234:

Ordered some bus bars and a buck converter from Amazon on Tue afternoon, arrived today Thu. How can they do it?

By being competent, unlike most NZ retailers that will just have someone at some retail shop pick it off the shelf when they have time and box it up to leave with a courier at some time.

Richard rich.ms

MikeAqua

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#3506033 25-Jun-2026 15:11

richms:

johno1234:

Ordered some bus bars and a buck converter from Amazon on Tue afternoon, arrived today Thu. How can they do it?

By being competent, unlike most NZ retailers that will just have someone at some retail shop pick it off the shelf when they have time and box it up to leave with a courier at some time.

Also, if Johno is in Auckland and the Amazon Warehouse was in Aus. Too easy. An Aussie retailer I buy from occasionally in Brisbane gets stuff to Blenheim in three working days

Mike

johno1234

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#3506454 27-Jun-2026 08:46

Update to this: I realised the old setup with a relay driven by 12V PIRs to switch the 24V lights was a bit old and crusty so I grabbed an old Shelly1 from the box of bits, set it to 12VDC power mode and used that instead. So the Shelly is powered off the cabinet 12V supply, and its dry contact relay controls the relay to switch the 24V lights on and off. The Shelly is flashed with Homekit-Shelly so is part of the Apple Home and the lights are automated to come on for 10min when the driveway camera sees something at night.

All the lights (9 24V driveway downlights and 2 12V bollard lights) are low power LED. Due to the voltage difference I drive the driveway lights off the 24V relay but the relay itself and the 2 12V bollard lights are driven directly by the Shelly output. I did think about the latter but it is rated to 10A for DC and the relay and LEDs are only drawing a fraction of that.

At this stage there's now no sensor at the far end of the driveway to activate the lights and it is too far away from the wifi for an IOT sensor. There's a bit of cable running down there so might be able to install a new PIR and connect it to the Shelly's unused press button. I think if I set the switch mode to "detached" the SW input won't switch the Shelly's relay but would be available as an event to Apple Home which can decide to turn the lights on.