While she accepted the need for maintenance work, she said a planned service should have an alternative power source.
Mrs Edmonds wrote to Tauranga Mayor Stuart Crosby and Tauranga MP Simon Bridges on behalf of United Video, Cherrywood Cafe and Cherrywood Takeaway, to ask for support.
Both Mr Bridges and Mr Crosby wrote to Powerco, urging the company to consult with the business owners.
Mr Crosby said in his letter that he shared the retailers' concern that their businesses would be affected.
Mr Bridges said the shop owners were "rightly in my view, perturbed that you have not consulted them regarding the timing and detail of it".
"It is their clear view that had you consulted a solution agreeable to everyone concerned could have been found. As examples of potential solutions I have been told that you could do the work at night time or ensure the businesses had generators so that they could continue during the maintenance."
But Powerco has not changed its stance that "the company did not provide generators for planned shutdowns unless there were 'exceptional circumstances' such as an emergency, or when customers were delivering essential services like schools or hospitals".
In a letter to Mr Bridges, Powerco corporate affairs manager Neil Holdom said the company had spoken with Mrs Edmonds several times in the last two weeks about the scheduled work.
"Powerco has had several discussions with Ms Edmonds and she has advised us that no time during the day would suit her for the shutdown as her business operates seven days a week.
"We are not able to charge customers for the provision of generators so we only provide generators in the event of emergencies or to facilities like schools or hospitals.
"Customers have the option of arranging their own generation if they choose and Powerco is more than happy to help them access expert advice and service when doing so."
Mrs Edmonds said she was disappointed the outage was to go ahead without a generator being provided.
