An electricity transformer, the size of a large motorhome, will be delivered by barge and beach to a National Grid substation at Trawsfynydd next month.

Part of Black Rock Sands Beach will be cordoned off and a rolling road closure will be in place as it travels through the area.

On Wednesday, 2 September, in a first for National Grid, the 128.5 tonne transformer is arriving via a barge and Welsh public beach to mitigate disruption of passing through Porthmadog Harbour.

"Transformers step up or step down the voltage of electricity between different circuits and play a vital role in helping ensure the UK continues to enjoy safe and reliable electricity supplies," a spokesperson said. "We need to make sure an old one, which has now reached the end of its life, is replaced."

A 330m temporary trackway is being laid on Black Rock Sands beach, Morfa Bychan, on Tuesday, 1 September and Wednesday, 2 September ready for the transformer to arrive at the beach by an 80-metre barge on the Wednesday.

A 10m wide corridor will be cordoned off for the trackway with two walkways for pedestrians to cross and vehicle access to the beach will be via Beach Road.

The transformer will remain at the beach, which will continue to have public access until Friday, 4 September and will then begin to make its way to Trawsfynydd Substation, arriving at around 12.30pm.

The journey and route, which is dependent on tide and weather conditions, has been carefully planned with our specialist haulage contractors and relevant authorities to minimise disruption to the public and road users.

It will be delivered on a specialist vehicle which is 31.5m long and will travel at approximately 12mph.

There will be a rolling road closure with a police escort to help manage traffic and make the process as smooth and safe as possible, but the exceptional size of the load and its speed of travel means there may be some delays.

National Grid, its delivery partner Mammoet, transformer manufacturer Siemens Energy, police and highways authorities have spent months carefully planning the delivery and route to keep disruption to traffic and people who live in the area to a minimum.

The transformer will follow this route on Friday, 4 September: Depart Black Rock Sands, turn right onto High Street, continue onto Britannia Terrace, continue onto A487, continue onto A470, arrive at Magnox Trawsfynydd.

It is recommended that anyone planning to use the roads mentioned above should try to find alternative routes or allow additional time for their journey.

National Grid project manager Wendy Williamson said: “Millions of people rely on us to supply their electricity without interruption, day in, day out so it’s important that we keep our substations and the equipment in them working efficiently.

"It’s a first for National Grid to have a transformer arriving onto a Welsh public beach, and certainly National Grid’s longest beach landing with 330m of track being laid, but we’ve been planning this for months to ensure we can deliver power reliably to the local area.”

To keep you updated and informed on the morning of the transformer movement, a broadcast text service will be available to remind people the main beach access will be closed and when the transformer departs from Black Rock Sands, when the main beach access has reopened and when the transformer has arrived at Trawsfynydd Substation and the delivery is complete.

It will also send you a text message if there are any delays in the schedule. To subscribe to this text messaging service, text INFO to +44 7860 027 814.