I was wondering if I should go with a fused distribution block or just a regular block with a 150amp in-line fuse will do it ?

( I have 2 amps)

 

the fuses are just there to protect the wiring, not the components. 150A fise?. I hope you're running 0 guage and not using a 150A fuse on 4 guage wire

 

Well, from different site, 150amp with REAL COPPER 4 gauges wire is borderline but OK.

 

WIRE
125amp on 4ga is the max recommended fuse size

 

Are your amps capable of drawing more than 120 A of current combined (based on the fuses in the amps)?

If yes then upgrade your wire.
If no then you're fine with a 150A on that line.

Rationale:
If your amps can draw more than 120A combined, then they can overload your wire. The fuse won't protect you from a gradual overload overheating and a fire could start because you're wire is insufficient. You will need a 125A fuse to protect against this.

If your amps draw less than 120A combined they won't over load wire . . . unless something in the amps themselves fry causing a dead short. But in that scenario the amps will blow their internal fuses before the wire is at danger of fire. The fuse is there to protect the wire. If the wire creates a dead short, it will create an instant amperage spike that will blow any fuse. The 4 awg wir won't be able to heat up enough to cause a fire before the fuse blows.

To that end, you don't really "need" each wire fused after a distribution block. If your block has a 4 awg in and multiple 8awg out, and one of those 8awgs shorts. It will blow the fuse protecting your 4 awg line.

Also, fuses add electrical resistance. Not much, but they do.

I've been running my last few systems with a fuse at the battery and nowhere else.

 

both amplifier are 90 amp. I know they don't do 180 amp because they can't be 100% efficient. So I was thinking about 150amp would be a fair bet.

 

you should definately be running 0 guage wiring then. or an idividual run of 4 guage to each amp