Fuse disconnect top or bottom

**Isetech** · 17-Jul-23, 05:15 PM

Had a look at a fuse disconnect today, identified as the top being "in" and the bottom "out".

So which way do you connect your switch disconnect, battery to the top or inverter to the top?

Battery is a power source and so is the inverter.

**Justloadit** · 18-Jul-23, 08:14 AM

I would say that the battery is the source, as it can under certain conditions provide far more current than the inverter under charging mode.
The important fact here I would say, is if there ever would be a situation in which under a load with in the capability of the fuse rating, the disconnect would be forced open. What will the arcing do to the disconnect contacts.
From experience, having seen the damage the arcing has done during the disconnect action, meant that the fuse disconnect device was completely damaged.

This is the reason that I use a battery disconnect switch as part of my wiring.
I use a Rotary Power switch similar to this item.
This is designed for the application, the fuses are another level of safety in the case that there is an electronic failure in the battery and inverter.

**Isetech** · 18-Jul-23, 08:28 AM

But we talking solar, you need special rules for the solar industry, just imagine the shyte storm if you mentioned installing a DC switch like you attached on a solar social media pltaform

**Isetech** · 18-Jul-23, 07:45 PM

I wired the fuse link, battery in the top, inverte rout the bottom. I will lable the fuse holder "inverter" bottom and "batteries" top.

When you look at how dangerous these homemade DC control boxes and how they are wired, I dont think a silly thing like in and out really matters on a fuse disconnect and its bidirectional, charge and discharge and its a "power supply" so the power supply should go into "line" or "in".

**Thys LOW Elektries** · 20-Jul-23, 04:59 PM

Inverter is not suppose to work without a battery So I would put battery at top

**Thys LOW Elektries** · 20-Jul-23, 05:07 PM

The next issue of concern is the fuses you have to pull out manually, apparently you use a special plier to do this though.
I prefer the blade fuses that have a handle you pull and the fuses disconnect automatically. Also, the handle protects you against an arc, if there is one.

**GCE** · 21-Jul-23, 09:35 AM

Originally Posted by Thys LOW Elektries

The next issue of concern is the fuses you have to pull out manually, apparently you use a special plier to do this though.
I prefer the blade fuses that have a handle you pull and the fuses disconnect automatically. Also, the handle protects you against an arc, if there is one.

There is a special handle that you buy to extract fuses and it has a shourd to protect you - LV-HRC Fuse Puller

Taking a blown fuse out is not a problem - Putting a fuse back on a fault can get interesting