I would like to disconnect the power to the 800i box if I switch the power off and unscrew black and red would that set off alarm when I throw mains back on 

800L box because it’s a constant beep and can’t stop the tpr if I unwire it will it set the main alarm off 

It would not be advised to remove wires from the alarm system if you don't know what your doing.

Removing power from the controls should normally trigger the alarms hold-off making the external alarm sound as if it where tampered with..

2 hours ago, Eddie Marshall said:

I would like to disconnect the power to the 800i box if I switch the power off and unscrew black and red would that set off alarm when I throw mains back on 

Is there an external bell box?

 

Do you have a fused spur ? That you remove the fuse