Free Pole Size Calculator for Level 1, 2 & 3 Electricians: What Size Pole Does Each Job Need?

We've put together a sizing reference for Level 1, Level 2 and Level 3 electricians that does one very specific job: it tells you what size pole or strut is required for each job — straight from the sizing tables in the Service and Installation Rules of NSW (SIRNSW, July 2018).

Use the sizing reference below to work out what size pole or strut you need — no sign-up, no cost, and it's handy to check on your phone at the job site.

Why pole sizing trips people up

Clause 3.10 of the SIRNSW sets out how to size the post, pole or strut that carries an overhead service line, and it's a two-step process that sends you flicking between tables. First, Table 3-8 converts your service size, conductor and span into a normal tension and a minimum strength rating — an "S rating" from S1 up to S32. Then Tables 3-9 through 3-15 convert that S rating into an actual physical size: a 100×100mm hardwood post, a 76×4.5mm Grade 250 steel pipe, a 100×100×10 angle iron strut, and so on — and the answer changes with the free length of the pole.

Do it by hand and it's five minutes of page-flipping with a few chances to grab the wrong row. Miss the mark and you've either ordered steel that's oversized (money down the drain) or undersized (a defect, or worse, a pole that fails under tension in a storm).

How to work out what size pole is required for each job

The sizing guide below runs through the whole Clause 3.10 process for you:

• Pick your service — 100A single-phase, 100A three-phase, 200A three-phase (95mm² LVABC) or 400A three-phase (2×95mm² LVABC).
• Note your span — any distance. Always round up to the next row of Table 3-8, so the result is always on the safe side.
• Get your S rating — plus the normal tension in kN, minimum breaking tension and expected sag.
• Pick your structure — Grade 250 steel pipe pole (Table 3-15), square timber post (Table 3-9), square timber strut (Table 3-10), or angle iron strut in Grade 250 and Grade 300 (Tables 3-12 and 3-13).
• Read off the size — the smallest compliant size is the one to use, with every other compliant size listed for reference, and for posts and steel poles the depth-in-ground figures from Table 3-5 for poor, medium and good soil.

A free sizing guide for Level 1, Level 2 and Level 3 electricians

Level 2 electricians (ASPs). This is the bread and butter — sizing private power poles for service upgrades, pole replacements, defect rectification and new overhead connections. A quick reference instead of flicking through the printed tables on site.

Level 1 ASP crews. A quick sanity check on service structures before ordering materials for network construction work.

Level 3 ASP designers. Confirm structure sizing assumptions in connection designs without digging out the printed tables — and pass the sizing details on to the construction crew with the design pack.

General electricians. Quoting a job that involves a private pole? Check the required size before you price the steel, then bring in a Level 2 ASP for the installation.

Builders ordering temporary builder supply (TBS) poles. If you're setting up a temporary builders supply for a site, the pole still has to be sized to the Rules. Check what you need before the steel order goes in.

Homeowners with a private power pole. If your pole is leaning, rusted or has copped a defect notice, this guide shows you what a compliant replacement actually looks like — useful context before you get quotes.

Tree loppers and crane operators. If your work needs the service line dropped and re-tensioned, it pays to know what's holding it up. We handle disconnect and reconnect work across Sydney.

What this guide covers (and what it doesn't)

This guide covers the five most common structures: Grade 250 steel pipe poles, square timber posts and struts, and angle iron struts in Grade 250 and Grade 300. It doesn't cover Grade 350 steel pipe (168mm+), steel square section or Riverton octagonal poles — for those, or anything unusual, get in touch at chris@highdemandelectrical.com.au and we'll size it properly.

One honest caveat: this is a guide, not engineering advice. The printed sizing tables have entries that drop out at longer free lengths, and clause 3.13 of the Rules requires a structural engineer in some situations. Always cross-check your printed copy of the Rules before certifying, and if in doubt, ask.

Need the pole supplied, installed and certified? HD Power Pole Sydney's team installs and replaces private power poles across Sydney — get a free quote at chris@highdemandelectrical.com.au.