Is leaving the relay always-on safe and prudent?

[Woggs1]

In this diagram it shows a relay hooked up, but it appears it is always on. It that safe and prudent? Is there any fire danger there? Maybe I should add a switch and only turn on the relay when I want to use inverter power?

Here is the relay I have on order:

 

[grizzzman]

That delay is rated as continuous. Leave it on.