The four-firm panel, which will handle general commercial and disputes work, is completed by long-time advisers Eversheds and Hammonds. Corporate and M&A advice will continue to be provided by CMS Cameron McKenna and Linklaters.
The National Grid held a beauty parade at the beginning of the year before deciding to discard Pinsents as a commercial adviser.
A Pinsents spokesperson said: "We have enjoyed working with National Grid and we are disappointed not to be reselected."
Those pitching for the panel positions were whittled down by group general counsel and company secretary Helen Mahy, who said the panel members would act as an extension of the in-house team.
Pinsents originally won a place on the National Grid general commercial panel at the end of 2004, along with Hammonds and Eversheds. Mahy confirmed that Pinsents would no longer be considered for new commercial instructions.
On the new panel, Hammonds and Eversheds will complement Wragges and BLP, which have been selected as full-service firms. Hammonds will advise on general commercial and health and safety work with Eversheds taking on commercial litigation and construction.
The National Grid will continue using Camerons, Denton Wilde Sapte and Martineau Johnson for specialist energy and regulatory work.