Power Cord gauge, Could it be the problem

I am far from being an electrician
I trade in a M2Tech EVO Clock against a PS Audio AC 12 power cord at HiFi Heaven.
It is a 8 AWG gage cord.
I thought ,  the bigger - the better. I had a good price for the clock , so why not a good power cord.
When l connected my McIntosh power amp in a power conditioner ( APC H15 ) , the power conditioner went out of order :  ´´ one of the inner relays is welded ´´ appears on the screen.
After chatting with the service department ,APC will give me an other one.
I have read on the web that this ´´ inner relays welded ´´ is not rare.
I connected my power amp with that cord in the wall socket and every thing is fine.
Now, I am afraid to reconnect the cable to the new power conditioner when I will receive it.

Could it be because of the cord gage  vs  the conditioner capacity ?
My amp was connected to the ACP before with McIntosh power cord without probleme.

Maybe , a short class  about power cords gage , would be OK 
I have read many many post here without finding an explanation.

Thanks