Understanding the implications of changing a cable route or specification

Making a small change to the route or specification of a cable after work has begun might not seem like a big deal, but it has implications in a range of areas. It’s not as simple as just digging a new trench and putting in a new cable.

When you change a cable from what has originally been specified and approved, you should expect the following implications when making the request:

Legal approval

The most complicated aspect is the need for new legal approvals in most cases. If the cable is being repositioned to a location outside of approved easement strip, you will need to go back to start.

The need for new approvals can snowball quickly. Even the small amendment can involve third parties including the Council and Highways. That can have serious time and cost implications.

Construction and programme delays

Even if your change doesn’t need new legal approval, there’s still a design change required. If it’s very minor, such as staying within the width of a footpath it can be fine. If it’s bigger than that, it is fundamentally different.

If cable lengths change, the volt drop, impedance and earthing arrangements will need to be recalculated. We might need to look at ground conditions to find out whether we need to duct or reduct the cable inits new location. All of that needs to go back to the DNO/IDNO for their approval.

Then, there could be further knock on effects. For example, does the new design require different traffic management? Everything needs to be looked at, even if it’s just a ‘small’ change.

Cost implications

The bottom line is this all costs you time and money. Things can be changed on site following approvals, but we always advise that our clients don’t do so on a whim.

If you can’t avoid making a change, it’s worth taking the time to fully understand what a seemingly simple request entails in reality. What might look like a small efficiency saving can have wide ranging implications leading to extra delays, time and cost.

In all cases, it’s vital that you stay in contact with us so we can give you the best advice and feedback. The Zenit team will always do what we can to minimise these delays, but if possible it’s always best to not move or change an approved cable in the first place.