Preparing an NEC4 ECC Option C Contract Data Part 1 for a project in the UK.
Under core clause 5 Payment, there is an entry in CD Part 1 associated with clause 50.7 for:
The exchange rates are those published in … on … (date)
Is there an industry recognised source for the exchange rates? and what date is normally used?
You are free to select any published exchange rates, if you anticipate needing to pay the Contractor in a currency other than the currency of the contract it would make sense to find out where the Client will be purchasing this currency from an select an exchange rate accordingly.
It would also make sense to chose a date where the exchange rates are already known rather than introduce the risk of a future date, most likely a date close to when you are issuing the tender.