{"id":63166,"date":"2022-07-11T09:26:19","date_gmt":"2022-07-10T22:56:19","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=63166"},"modified":"2025-07-15T07:58:05","modified_gmt":"2025-07-14T22:28:05","slug":"cable-conduit-solar-inverters","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/cable-conduit-solar-inverters\/","title":{"rendered":"Conduit & Solar Inverters: The Good, Bad & Fugly"},"content":{"rendered":"
\"Nasty

Looks fine from my house\u2026<\/p><\/div>\n

The $200, 2-inch thick, spiral-bound ‘AS\/NZS 3000 Electrical Installations’ is also known as The Wiring Rules, The Book, or The Bible. Electricians use it to beat each other over the head when they feel a fellow sparkie has strayed from the true path of holy electrical compliance.<\/p>\n

In the same way that electricity seeks the path of least resistance, some tradies will bend or ignore the rules in The Book that a proper tradesman1<\/a><\/sup> will follow.<\/p>\n

The 50mm-Or-Conduit Rule<\/h2>\n

One of the Golden Laws outlined in The Book is ’50 millimetres’. Electrical cables in a wall must be more than 50 mm from the surface. The concept is that, even if wiring is hidden behind a surface, it will still be quite safe to drive a 2-inch nail into that surface.<\/p>\n

But what about screws bigger than 50 mm? They are the reason it\u2019s illegal to fix or restrain wiring inside a wall cavity. If you unknowingly attack the cables with a 75mm screw, the cables should be free to move aside.<\/p>\n

What happens when you can\u2019t place your cables 50mm from the surface? Then extra protection is required, most often conduit in a variety of forms; but sometimes a continuous sheet of steel can be a more subtle solution.<\/p>\n

The Conduit-For-Solar-Cables Rule<\/h2>\n

Now for solar cables, there are even more rules…<\/p>\n

My previous post explained that solar\u00a0DC cables must be encased<\/a> in heavy-duty conduit as soon as they enter the roof cavity. \u00a0That rule continues all the way to the inverter. Even if the DC cables go down the wall inside a double brick cavity, conduit is required.<\/p>\n

Once the conduit reaches your isolator, it must enter from the bottom. The solar inverter (known as Power Conditioning Equipment or PCE for those fans of TLAs) might have plugs or conduit entries, but either way there can be no more than 300mm of DC cable exposed for your dog to chew on.<\/p>\n

\"Conduit-For-Solar-Cables<\/p>\n

The Drain-Valve-In-Your-Conduit Rule<\/h2>\n

One rule that has recently caused some in the industry to insert an expletive before describing the actions of the Standards Committee relates to drain valves.<\/p>\n

Yes, I know that sounds more like a plumbing standard.<\/p>\n

Thing is, with all this mandated conduit, the solar standard in effect decrees that we install plumbing from the roof (where it\u2019s wet) to the electrical equipment (where there’s stuff we’d really like to keep dry). To mitigate the inevitable effects of condensation filling the lowest point with water, (usually the inverter or isolating switch) new standards specifically prohibit the simple, age-old practice of weep holes being drilled. The new standard requires either the conduit to be left open at the inverter end (simple) or drain valves to be installed. When the standard came out, these devices were not even available. \u00a0 \u00af\\_(\u30c4)_\/\u00af<\/p>\n