There will be significant traffic delays due to traffic movements delivering components to the Garreg Lwyd wind farm development.
Russell George, AM for Montgomeryshire, has previously warned the Welsh Government about the potential problems with the proposed route.
On Friday (5th August), a trial will be carried out between Liverpool and through Montgomeryshire to the Garreg Lwyd site on the Radnorshire/Montgomeryshire border to assess whether the numerous abnormal and heavy goods vehicles can manage the route, in advance of the full turbine delivery programme, anticipated to begin on 12th September.
These abnormal loads will travel along the A483, and travel along Pool road, over the Kerry road roundabout, and up Llanidloes road. The abnormal loads will then be required to travel under Nantoer bridge on the A489.
This particular bridge is also well known for large vehicles having difficulty passing under it and blocking the main trunk road.
Responding ahead of the trial run, Mr George said:
"I've had long held reservations about this development due to the transport implications for Newtown. Indeed, on transportation issues alone, the application for the wind farm should have been rejected.
"I have also repeatedly raised concerns about the consequences of the proposed route for these abnormal vehicles with the First Minister. Despite the assurances provided to me, I simply don't believe that the Welsh Government has taken the concerns I have raised seriously.
"The movement of these vehicles will not only cause huge disruption in Newtown but also the wider Mid Wales area. In particular, I have concerns that the route will be navigating under the Nantoer bridge, a bridge under which numerous HGV and large vehicles have got lodged previously.
“In my initial letter of objection, well before the Welsh Government approved these applications, I warned of traffic chaos and regrettably they have simply not taken into account the warnings from me and others.
"The developers and Welsh Government Ministers should not only be concerned about the wind turbine components getting to their destination, but should also be aware of the significant congestion that will be caused behind the delivery vehicles and the wider effects which this will have on the Mid Wales economy."