I hate that WFCO fuse board! (with 12v ATC fuses)

**rickst29** · 06-23-2024, 07:09 PM

Most of the 'mounting tabs' for my 18-year old WFCO 'Power Center' have broken off, because the plastic has become brittle with age. I replaced the pwer converter section log ago, but I'm now thinking that I should discard and replace the entire panel -- primarily due to "issues" with design of the 12V section, and the presence of a neutral bus bar near the fuses and their downstream wires.

The first problems involve the 12V input power ports along the left side of the fuse board. They also use ATC fuses, even though the maximum size for an ATC fuse is only 30A. vthere are two such ports. In original wiring, one connects the main Main Converter Board Assembly ("MBA") 12V outpt wire, and the other connects the "12V" wire from the battery bank.

The original WFCO "55A" Converter Board was never capable of putting out 55A for an appreciable time, and a "30A" fuse was adequate. But some of its replacement boards can easily burn out that fuse, and can even burn out a nonstandard "40A" version as well.

If you attempt to support more than 40A on either of those ports, the small contact area provided by the legs of standard ATO/ATC fuses is inadequate. (The fuse legs are not clamped in place using screws under high pressure, they are only held by weak spring clamps.)

But even 40A requires 8-AWG wire size, and the WFCO box provides ZERO room at the side of the board to bring 8-AWG wire ends into those terminals. I have currently twisted those input wire ends into crazy shapes, and drilled extra holes in the back of the WFCO box to provide "easier" wire entry. But it looks (to me) like a problem waiting to happen, when road travel causes those over-bent wires to distort and loosen.

For the case of a high-powered converter board sending power to the battery cable, through the terminal board, the "hot" plane of the board itself might have issues (with almost 60A in and maybe almost 60A out, all through loose and small fuse connectors and severely bent terminal wires).

The second set of problems involves a lot of Neutral "12V Grounding Wires" coming into the same area - the front of the 12V wiring section, where many have been attached to a shared bus bar. (WFCO more recentrlygot rid of this design defect, but my old one still has it). The 12V fuse board itself also has a gigantic lug for connection of two big Grounding Wires", even though the only use of grunding on the fuse board is to light up the tiny LED warning light when a fuse fails.

That's all crazy. The only "grounding wire" into the board should be small (no larger than 14-AWG) and the bus should be separated by a great distance. None of the other white "12V neutral grounding" wires should have ever entered the front section of the WFCO box at all.

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I need less than 7 "12V" fused ports in the area under the bathtub. ( which is independent of the original TM wiring. I plan to replace the old fuse board with a pair of these 4-port "maxi-fuse" blocks: https://www.ebay.com/itm/122894438164. Maxi fuses have much larger legs, and they can be bought to support much higher amounts of current. (Although they also support small current limits, such as '5A" maximum)

The power handling in these 3x4 maxi boards is huge. I will connect two block together using a short segment of AWG-2 (ports are provided on the side), and then use 8 "downstream" ports to replace the WFCO board. (I'm adding a 3rd block up front, near the batteries, but that location is independent of the original TM wiring.)

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At the same time I replace the "12V" fuse board, I will replace the fully-populated "12V and frame grounding lug" along the inner right side of the WFCO with a new lug - probably with more ports. I will also be replacing the 120-VAC section with a new Din-rail mini breaker box. (This one: https://www.amazon.com/gp/product/B0CPV9NQ2M It includes Neutral and Grounding bus bars with more ports than the old WFCO box provided.

**rickst29** · 07-06-2024, 05:39 PM

https://www.amazon.com/gp/product/B007ZZGSDQ/.

Less than $7 each (on sale), the power handling is adequate (except from the gigantic Inverter) and they provide 12 ports each. I'm installing one under th4e bathtub seat (lower wall, as a part of this WFCO "power center replacement" project.

I will install the other in the battery storage area. I have a lot of 12V "grounding wires" in that area. Several wires are smaller than the 14-AWG wire size recommended on these bus bar ports, I will be using multiport WAGO connectors to join groups of tiny wires together, with a single larger wire (from the same WAGO conmnector) going into the bus. WAGO connectors are spring-loaded, and very reliable within travel trailers. Each WAGO supports up to 30A, although it's hard to fit a 10-AWG wire into he standard ones. I'll be using 12-AWG, upstream, and my tiny interconnect "12v grounding wires" wires carry a much smaller total amount of current.

**rickst29** · 07-06-2024, 07:10 PM

Quote:

Originally Posted by rickst29

...

I need less than 7 "12V" fused ports in the area under the bathtub. ( which is independent of the original TM wiring. I plan to replace the old fuse board with a pair of these 4-port "maxi-fuse" blocks: https://www.ebay.com/itm/122894438164. Maxi fuses have much larger legs, and they can be bought to support much higher amounts of current. (Although they also support small current limits, such as '5A" maximum)

The power handling in these 3x4 maxi boards is huge. I will connect two blocks together using a short segment of big wire (maybe AWG 1/0). "Main Bus" Ports are provided on the sides of the main bus, as well as the back).
I can then use the 8 total fused "downstream" ports to replace the WFCO 12V fuse board. (I'm adding a 3rd block up front, near the batteries, but that location is independent of the original TM wiring.)

I'm installing today and tomorrow. My only problem with using these 4-port Maxi-fuse mini-boards occurs with my long "12V" wire, coming from batteries (up front, in couch storage). My 4-AWG wire travels within LiquidTite conduit underneath the TM floor, and it is too large for the fused ports on the 4-way Maxi Fuse block. It will need a separate external fuse. From the other side of that external fuse holder, I will need only a short segment to reach into one of the larger "main bus" ports of the first fuse block (using a larger wire size.)

My total of 12V loads "up front" should not exceed around 70A, as a maximum value in either direction. (The PD charger can put out only about 60A, and the maximum on 12V "downstream ports" could never exceed even 60A in the OEM configuration - with both batteries and the "Converter Main Board supplying 30A each through the ATC-fuse-limited ports on the WFCO 12-VDC fuse board.) My long wire size from the batteries is fairly large AWG-4). It can fit one of the "main bus" 12V port on the new 4-fuse blocks perfectly, but it cannot be fused within that block - the fused ports are n't big enough.

On hand, I have an ANL fuse block for large bare wires. The wire terminals within that block are too large to a handle my 4-AWG wire, so I will need to "bulk-up" bare end of my AWG-4 main wire (coming from the battery area) using solder and at least one sleeve (maybe two) so that it can fit tight into that tight into that fuse holder. Per above, the other end of the ANL fuse block can be used with a short segment of full-sized wire i(probably 1/0) into the first of the "maxi fuse blocks".the maxi-fuse block.

ANL fuses are sold with very high ratings, up to 400A, even though the LEGS on the fuies are too thin to support that amount of current. (I don't trust them to handle current higher than about 120A. They are also all slow-blow fuses.) Under the tub, in that fuse holder with with 4-AWG wire, I will replace my current oversize ANL fuse with an "80A" ANL fuse before my next trip.

Wavery · 07-06-2024, 07:40 PM

Hey Rick........ how do you REALLY feel about that fuse board? Come on now..... no holding back..

**rickst29** · 07-06-2024, 08:31 PM

The fuse board is marginal, with a plane supporting (maybe) 120A total current. But the use of ATC fuses on the power-in ports, combined with the inacessability of the upper left 12v port, have made it a show-stopper for me.

The fact my WFCO cabinet screws are nearly all broken is one additional factor in my project. The "too-small" bus bars in the 120-VAC section (for both current carrying "neutral" and green/bare safety ground) has been another. The use of somewhat primitive AC circuit breakers (not meeting Class-C response time requirements) was also a factor.

The "last straw"was not a WFCO problem, but it was related to my hiding bigger bus bars and "12V power distribution blocks" behind the WFCO unit, One of my "12V connections" got loose during roadway travel on my last trip, I arrived in camp with 12V dead at the WFCO. (No water pump, no lights.)

Pulling the busted-up WFCO from the wall was difficult in the dark, due to all the broken screw holes with oddly combined metal versus plastic "screw support" metal parts. The fact that I had two hard-too-see 12v wires into teh WFCO board, rather than just one, was the last straw.

I fixed it in about an hour of misery, but I sweared "never again". Behind the WFCO, I also have an MPPT Solar Controler. It doesn't have a remote monitor ingterace, and it pretty much "uncontrollable" when I can';t see the LED pAnel and press buttons. (I can also expose the the front of that SCC unit underneath the tub,. when I get rid of of the "big and broken WFCO unit).