I kinda hate to post this, but I feel it's important information that members should be aware of. This came to my attention as I was exchanging PMs with another member as he was trying to pick out a fuse panel, with this being one of his choices. There was a fairly recent thread with some melted wires and a melted internal buss in the panel and I think it was this one... Universal Style Pre-Wired 20 Circuit Fuse Block Part No 30003 – Painless Performance This Painless panel is everything I hate about the aftermarket harness suppliers as it's a far too typical design, although it may be worse than some others. IMO it's a total POS. They don't furnish an internal wiring diagram for it, but if you read the instruction directions you can figure out its limitations (many). A few highlights from their 'manual'... Item 9. If you have an alternator with an output of more than 65 amps, they want you to add another wire between the alternator and the battery or solenoid. First, connecting the alternator output to the panel is a bad idea for multiple reasons and adding this second wire only compounds it, which I have gone into in other threads. Basically they're admitting that this panel can't handle any loads beyond this amount without damage to it. I'll explain why this connection to the panel is there further down Item 10. This panel is internally split, but ALL of your key-switched loads go through this #12 wire. Properly derated, this limits you to 16 amps for all of them. Item 30. This wire is supposed to supply ALL power to the panel, although that's really not true. Being a #10, if properly derated its only good for 24 amps. Note that they 'strongly recommend' that it be fused at 50 amps at the battery/solenoid. But assuming the 50 amps is available, that means your average circuit size is limited to a mere 2.8 amps each if using all fuses. This is actually only a 18 circuit panel, that's how many fuses it has. So that means that some relays are in your future. Likely candidates are headlights, fuel pump, heater/AC, and cooling fan. If you have an amplifier for your radio, that's another one. Maybe more, depending on what actual loads are. All of these relays will have their own main power feeds at the battery/solenoid and should be fused at that point... defeating the idea of a unified panel. If your total circuit count is lower, a smaller panel would be a better choice; you're paying for capacity you won't use, although you may still need relays depending on the panel design. That wire in item 9? The theory behind this is if the load on the maxifuse (assuming it's present) gets too close to its rating (risking blowing it), this wire (which is UNFUSED) will supply the 'extra' until the load drops back to 'normal' (hopefully quickly). If the fuse does go or you get a poor connection at the fuse terminals or the wire in item 30, ALL of the load will fall on this #12 and a fire along with a damaged fuse panel may ensue... If you have one of these wired the way they say, I will highly recommend that you... 1. Remove both of the wires in item 9. 2. Install that 50 amp maxifuse if you don't already have one. 3. Do load calculations for EACH circuit and remove enough of them from the panel (feeding them through relays with separate power supplies) to drop total connected load to below 50 amps. You can use the existing circuits in the panel to switch the relays or simply gang the relay coil power to any switched hot.
@Crazy Steve Thanks for this. Chrysler (and others) loved the amp gauge to have all the load go through it and the bulkhead connector. It has over time proven to be a hazard. I know you have addressed this in previous threads, but when you say to do load calculations, providing a source for this that can be used by the widest cross section would be helpful. I replied to another wiring question and found widely different numbers. https://www.jalopyjournal.com/forum...and-wiring-info.1120201/page-30#post-15673293
Interesting. In my mind, it seemed most folks were happy with them and recall seeing many recommendations. Do you know what kind of wire they use? Back in the day, for all of our mobile HVAC wiring products , I think I spec’d out SXL?.
This panel should have maximum total current being drawn specification listed and is a warning for the customer.
Steve, what is your favorite brand of aftermarket wiring panel/kit? Something simple like most HAMBers would need without a couple dozen circuits for modern conveniences?
EXACTLY. and it should have it spelled out for each circuit. The descriptions and specifications for most panels I have seen SUCK. This entire wiring thing is hard enough to do right without having to figure out their hidden shortcomings. To me it seems these wiring companies spend more time trying to sell us what they want to sell rather than what we want to buy. I am going to plan my wiring job out and then see what panel works best for me.
What is even more to add to this is the length of time that is acceptable for a fuse to open (blow) according to the SAE standard. The response time of a standard SAE automotive fuse (like those found in cars) varies depending on the current flowing through it, but it generally falls within a range of 0.75 seconds to 120 seconds at 135% of its rated current according to State Electric Supply Company and Circuit Specialists. At higher currents (e.g., 200% of the rated current), the opening time decreases significantly, potentially ranging from 0.15 seconds to 5 seconds, according to Circuit Specialists. Here's a more detailed breakdown: At 110% of rated current: . The fuse should be able to carry this current continuously for at least 100 hours according to Circuit Specialists. At 135% of rated current: . The fuse should open in no less than 0.75 seconds and no more than 1800 seconds (30 minutes) according to Circuit Specialists. At 200% of rated current: . The fuse should open in not less than 0.15 seconds and no more than 5 seconds according to Circuit Specialists. At 350% of rated current: . The fuse should open in not less than 0.08 seconds and no more than 0.50 seconds according to Circuit Specialists. The exact opening time for a specific fuse at a given current can be found in the fuse's time-current characteristic curve, which is often provided by the manufacturer. These curves show how long it takes for a fuse to open at different current levels according to Littelfuse. So, there was a fuse recall from Harbor Freight several years ago that was a kit of 60 fuses of varying sizes. They would not blow at all! A 20 amp fuse being hit with 60 amps melted the plastic off but did not open after 15 minutes! Beware cheap fuses from unknown manufactures from whatever source on line you choose!
I haven't used Painless in years, it was one of the first aftermarket panel kits back in the day. Now it's just American Auto Wire or a DIY job.........................
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