In the main, they catch personnel interrupting new temps in seconds (6,4)

'in the main they catch' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'personnel interrupting new temps in seconds' is the wordplay.
I cannot really understand how this works, but
'personnel' could be 'hr' (Human Resources) and 'hr' is found within the answer.
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is found within the answer.
an anagram of 'temps' is 'mpets' which is located in the left over letters.
'seconds' could be 's' and 's' is present in the answer.
A single letter 'i' remains which might be clued in a way I don't see.
This explanation may well be incorrect...

Can you help me to learn more?