Appendix 4, section 6.1 equation 6

Note 1 to Table 4E2A tells you to derate the cable to 70 degrees unless the terminals can handle  90 degrees, the cable won’t be running at full temp, but to be technically correct the cable needs to be treated as 70 degree cable.

As it’s a temporary installation HO7RNF cable is probably the correct cable to use, which takes you to one of the 4F tables, but no one would generally expect someone to make a 300 metre long “extension lead” with 1.0 mm conductors, so you won’t find entries for 1.00 mm cable as it’s pretty flimsy.

You have not not said what the actual load is, an appliance or lighting or what period you are defining as “temporary“. 

I might be considering 2.5 mm H07RN-F  as a fairly robust cable for a temporary supply that can be reused. 

Note 1 to Table 4E2A tells you to derate the cable to 70 degrees unless the terminals can handle  90 degrees, the cable won’t be running at full temp, but to be technically correct the cable needs to be treated as 70 degree cable.

As it’s a temporary installation HO7RNF cable is probably the correct cable to use, which takes you to one of the 4F tables, but no one would generally expect someone to make a 300 metre long “extension lead” with 1.0 mm conductors, so you won’t find entries for 1.00 mm cable as it’s pretty flimsy.

You have not not said what the actual load is, an appliance or lighting or what period you are defining as “temporary“. 

I might be considering 2.5 mm H07RN-F  as a fairly robust cable for a temporary supply that can be reused.