Input needed with cause of blown Rockford Power T amp and sub

[BlackHawk1]

Hello. I hope you can provide some help with this situation. This is all new equipment minus the head unit. A friend of mine is running the system below (links to all items provided) on a 100 amp inline ANL fuse that the car audio install shop put in. The air conditioner was turned on in the car while the music was playing at a medium level and the fuse blew. We checked the amp owners manual and it calls for a 150 amp inline ANL fuse. Did the shop screw up by only putting in a 100 amp ANL fuse? They said a 100 amp fuse should have been fine and that the manual stating a 150 amp fuse is just the max size fuse you "can" put in. The shop then put in a 150 amp fuse, the system was turned back on (without the air conditioner running) and no music was heard. All he got was some noise and smoke. The install shop determined that the amp had fried. They said it must have been a flaky amp. Take note that the 150 amp fuse did not blow when the amp fried. Also note that the amp (a Rockford Power series) does not have fuses of its own built in like most amps I've seen. The car's electrical system was then tested and it checked out A-OK. A few days later a replacement amp was installed, the stereo was turned on, and now there's no sound from the sub. The install shop determined that the the sub is blown. It obviously went at the same time the amp did, but we just didn't know that at the time. The install shop is now claiming that the sub is junk and it's the reason the amp blew in the first place. I find this hard to believe. The sub blew the amp?! Really? The sub is a single 4 ohm sub that handles 250 watts RMS and 2 of the channels on the amp are running the sub bridged. In this case a total of 300 watts is going to the sub correct? The other two channels are running a component set up front. Here are some specs on the amp---

*4-channel car amplifier

*100 watts RMS x 4 at 4 ohms (150 watts RMS x 4 at 2 ohms)

*300 watts RMS x 2 bridged output at 4 ohms (2-ohm stable in bridged mode)

We still believe that the amp was the issue and not the sub. Of course the install shop does not agree. Feedback on this situation is greatly appreciated. We thank you!

The installed system---

1. Components Focal Polyglass 165 VB: http://www.crutchfie...-VB.html?tp=106

2. Sub- Focal SB30A1: http://www.crutchfie...-A1.html?tp=112

3. Amp: (Power T600-4) http://www.crutchfie...ard.html?tp=115

4. Pioneer AVH-P3200BT DVD receiver: http://www.crutchfie...VH-P3200BT.html

5. Rockford Fosgate PEQ Amp Remote Control: http://www.crutchfie...ol.html?tp=1451

I must say that the system sounded very good when it was working LOL! I was surprised he bought this sub, but when I heard it, I actually liked it a lot. It wasn't that one note boomy bass like I've heard so many times before. We hooked up a single 10" JL Audio sub to this system and while it may have played lower and louder, it just didn't have the same sound quality as the Focal did.