Safety when digging
Check for power and communications cables before you begin
Before you begin any digging work it’s important to find out where Northpower’s electricity and communications cables are. Overhead lines in the area don’t automatically mean an absence of underground cables.
There are five steps to follow for safe digging practice outlined here.
Cables can be located at different depths
Firstly, it’s important to note that our cables are laid at different depths in the ground. These may vary from just under the surface to over 1200mm deep.
We cannot guarantee the depth of any cable because alterations to the ground cover may reduce or increase the depth. We recommend that you do not rely on finding buried marker tape when you dig, as this may not be present if the cable was installed by a directional drill or thrusting.
Please do not use toothed excavator buckets when digging close to underground assets.
Step 1: Obtain reference maps
Please visit www.beforeudig.co.nz to request plans before you begin work. They will then email you the free reference maps that indicate the approximate location of underground cables, and provide you with a sequence number.
It’s important to get in touch with Before U Dig plenty of time before you start work, in case you need a cable location service outlined below (Northpower requires a minimum of two working days’ notice for this.)
The accuracy of maps cannot always be guaranteed as road re-alignment, reconstruction, alterations to ground cover and property boundaries can all affect accuracy. This means that you will have to confirm the location of our cables within your work site before you begin any work.
Please note that these reference maps are valid for 28 days from the date of issue and new maps have to be requested after 28 days.
Step 2: Locate assets in relation to your worksite
If your worksite is indicated within 10 metres of our cables you must carry out a cable/pipe location to identify the approximate location of the cables.
We can come to site and locate the cables for you, marking them with dazzle and advising approximate depth.
Please apply online for a cable location service and allow at least two working days to process your request. If you need to locate underground cables and pipes urgently or on a weekend or public holiday please contact us.
Please note your responsibilities under the Health and Safety at Work Act 2015, where you must establish the location of underground services before commencing excavation. You must also locate the services by ‘potholing’ using recognised techniques to expose cables and to continue working safely.
Note: A minimum fee of $174 plus GST is charged for all on-site cable locations. If it takes longer than one-hour, additional time is charged at $44 plus GST for every 15 minutes thereafter. . However, if the cables are shown to be our core distribution cables and are on private property and/or your neighbour’s service lead runs through your property, we’ll mark these out free of charge.
Step 3 - Confirm the physical location of cables and pipes by potholing
Potholing requires using recognised hand digging and/or hydrovacing techniques to expose the cables and pipes. These techniques are less likely to result in a strike on the services that cause serious damage to cables and pipes.
For your own safety, you must pothole with caution. If you damage a cable or pipe please report this to us immediately by calling 0800 10 40 40.
Remember to check for other services coming off a main such as water and private service cables and pipes.
Step 4: Use a designated safety observer
All works within two metres of high voltage network electrical cables, or any Northpower critical electricity or fibre lines require a Northpower stand over at the contractor’s cost.
Step 5: Continue working safely
- if you discover marker tape or protective covering for unmarked cables, you must pothole to expose the cable
- always assume that cables are live until confirmed otherwise by a Northpower representative
- if you want to lift, lower, shift or remove any cable or expose a cable so that more than one meter is supported, specialist involvement is required by our engineering team
- backfill should be a recommended stone-free soil or approved thermal backfill
- don’t forget to put mechanical protection and warning tape back when reinstating
Excavating near power poles?
If you need to dig near power poles, please read more about the important rules and things to do before you start.
Digging near power poles
Download our safe working around electricity guide
Our guide to working safely around Northpower’s electricity and communications networks is a great resource to download and take with you on the go to help get your job done safely.