Bridged Amps - Quick Question

[Tenacious]

efficiency is a moving target that decreases as the amp gets hotter.
this fuse BS is why I say all classes should require clamping amps. pretty easy with modern split-core C.T.'s or logging clamp meters.

Agreed. They seem to be pretty lazy when it comes to the classes you are put in to. Anywhere from a 75a to 175a fuse keeps me in the same class...

 

[tommydh 10+ year member]

efficiency is a moving target that decreases as the amp gets hotter.
this fuse BS is why I say all classes should require clamping amps. pretty easy with modern split-core C.T.'s or logging clamp meters.

Nice tool avatar to start but finally you get it. Im looking at power draw in a purely electrical view, not looking at what the electronics are doing. Plus most fuses have a built in surge factor. In a short period you can hit that current and be ok for a litttle while if you buy Quality fuses they hold up better than the chinese ANLs or what it is you have to run. I am not competeing so I use industrial fuses and switches that are used in the cranes at my shipyard i worked at.

 

[keep_hope_alive Premium Member]

Nice tool avatar to start but finally you get it. Im looking at power draw in a purely electrical view, not looking at what the electronics are doing. Plus most fuses have a built in surge factor. In a short period you can hit that current and be ok for a litttle while if you buy Quality fuses they hold up better than the chinese ANLs or what it is you have to run. I am not competeing so I use industrial fuses and switches that are used in the cranes at my shipyard i worked at.

yep. as an EE i have to choose fuses based on their time/current curve characteristics.

 

[tommydh 10+ year member]

yep. as an EE i have to choose fuses based on their time/current curve characteristics.

I do know what you mean but you know that thereare better stuff than what most use but when limited to competition rules you have to use that. When my stock battery finaly goes I am upgrading all my wire to xo jacketed "welding" cable although this is more fore locomotive and crane apps.

 

[tommydh 10+ year member]

yep. as an EE i have to choose fuses based on their time/current curve characteristics.

I am a liscenesed Master Electrician and also have to choosse best fuse/overcurrant protection drvice per need plus I teach 1st year apprentices

 

[keep_hope_alive Premium Member]

I am a licensed Master Electrician and also have to choose best fuse/overcurrent protection device per need plus I teach 1st year apprentices

That's great! Do you get into arc flash and selective coordination calculations and software also? We use SKM Power Tools.

I agree there are much better quality products available than what the car audio market has available. Much better wire, better fuses, better connectors, etc.

Keep in mind that regardless of the type of wire used, the connection method in a car is limited to the 60 deg. C column in the NEC Ampacity tables. If someone decided to use compression lugs on both ends of the wire, I think the 75 deg C. column could be used.

 

[tommydh 10+ year member]

That's great! Do you get into arc flash and selective coordination calculations and software also? We use SKM Power Tools.
I agree there are much better quality products available than what the car audio market has available. Much better wire, better fuses, better connectors, etc.

Keep in mind that regardless of the type of wire used, the connection method in a car is limited to the 60 deg. C column in the NEC Ampacity tables. If someone decided to use compression lugs on both ends of the wire, I think the 75 deg C. column could be used.

I have taken arc flash classes as part of my highvoltage splicing and termination training. Along with the ampacity tidbit all of those USING sheet metal screws for grounds are just asking for failure. According to NEC 250 you must have at least 5 threads engaged to be considered a ground as well as the article that states Sheet metall Screws may NOT be used as grounding means. Also on the ampacity why is it that car audio cable manufactures do not have to follow the same standards.

 

[keep_hope_alive Premium Member]

I have taken arc flash classes as part of my highvoltage splicing and termination training. Along with the ampacity tidbit all of those USING sheet metal screws for grounds are just asking for failure. According to NEC 250 you must have at least 5 threads engaged to be considered a ground as well as the article that states Sheet metall Screws may NOT be used as grounding means. Also on the ampacity why is it that car audio cable manufactures do not have to follow the same standards.

it is annoying that car audio manufacturers have seemingly no standard for AWG.

 

[tommydh 10+ year member]

it is annoying that car audio manufacturers have seemingly no standard for AWG.

Very and its even worse when you ask for their specs and insulation rating