DIHOOL DC breakers

[fmeili1]

I've installed two single pole DC breakers with 160A for my 2 pairs of R4875G1 DIY Chargeverters. They look exactly the same like the single pole 160A DIHOOL but they are from HESCHEN (same size, same weight, etc.). You need a lot of force to toggle the switch - they are really robust also the screw terminals. No issues so far and I'm happy with these breakers. They stay cool with 155A tested. They are about 40% cheaper compared to DIHOOL (the pictures here and here shows them installed - the first picture link also showing thermal images while at 155A). They are also available in 2-pole versions.

 

[PVGeezer]

Thanks but Im planning to use these on hybrid inverters so what i would like clarification on is if the Dihool DHM1X is polarized (unidirectional power flow) or non polarized (bidirectional power flow)?

 

[fuzzmunky415]

Thanks but Im planning to use these on hybrid inverters so what i would like clarification on is if the Dihool DHM1X is polarized (unidirectional power flow) or non polarized (bidirectional power flow)?

From web page here:

DHM1X-2P Molded Case Circuit Breaker

www.nsbjd.com

I will say this appears to be a rebadging company, and this looks curiously the same as the TAIXI breakers that are in the breaker box Will recently panned, as they didn't perform to spec.

edit: now I can't find where he tested the breakers....edit 2 Nada...I must have dreamed it...I was left with the impression I couldn't rely on these breakers beyond on/off, they wouldn't protect the wires?

 

[PVGeezer]

Yep that document came with the breaker. But check the notes at the bottom..Looks like they contradict the schematic which calls out the load connections at the bottom. Hence my question.

 

[fmeili1]

Both DIHOOL and HESCHEN MCCB's are non-polarized.

 

[robbob2112]

Here is a teardown of that type... I've opened up a number of them... the good ones have good fit and finish...they have lubricant at the contact points for the moving parts. They all have arc chutes and the contact points appear to be plated with sintered tungsten. The rocker arm of all I've opened is made from aluminum... although I might need to open a few back up and check that...all of the places where the cables bolt seems to also be aluminum. Some have a nut pushed into the back side for the screws to thread into.

Other than edges that don't meet properly there isn't a way to tell the good from the bad other than brand... taixi, tomnz, and dihool are all good brands... the no-name like picture and chintz aren't great.

The better ones have an extra piece of what looks like epoxy board to direct the arc as it goes across the divider. This protects from the arcs from hitting the plastic sides. I intend to do some testing when I get setup to see if they flip at the rated current...

1-pole verse 2-pole. - the NEC says a floating system should have both poles disconnected at the same time - to me this means all battery systems that don't have the negative pole tied to the ground or chassis of a vehicle. In those system 1 verse 2 pole is optional. I should note - this topic has been debated several times and we agree to disagree.... I use 2-pole where I use them and other advocate to never use anything but 1 pole in a battery system

Post in thread 'Robbob2112 Answer thread'

Dec 6, 2024

Anatomy of a MCCB - this one was $36 on aliexpress


With the cover off.


The arc chutes, 1/2" wide and 1.25" tall




Where the arc chutes go.


Very good quality and I wouldn't hesitate to trust it as a switch.

Below are some additional brands

Top quality is TOMZN closely followed by TAIXI.... then the ZOII but it doesn't have lubricant at the moving points... and the BAOYI in a distant last place.... CHINTZ comes in below the TAIXI and TOMZN but higher than the ZOII





All of the ones I have in my possession are marked for line/load...

• robbob2112

• 

 

[PVGeezer]

Thanks. Excellent post.

What I don't get is why the Dihool DHM1X is marked with line and load sides if it's bidirectional and unpolarized? Just makes me suspicious. Any thoughts?

I might try the other version which looks like it's not marked that way. Gotta love the Amazon return policy.

I don't see the debate on one vs 2 poles for ungrounded battery circuits. The NEC is explicit on this point, all ungrounded current carrying conductors subject to overcurrent faults need OCPDs. Nothing special about one polarity over the other. It's pretty easy to do a fault study on a battery circuit and see why you need to protect both sets of conductors.

 

[PVGeezer]

Both DIHOOL and HESCHEN MCCB's are non-polarized.

Seems that way but then why have line and load side markings?

 

[robbob2112]

All of the ones I have in my possession are marked for line/load in one way or the other --- they are polarized..... This tracks with only having arc chutes at one end...

the big 4-pole breaker on the left also includes a 24v remote trip relay so it can be controlled by a dry contact off an inverter or code red or cerbo GX box....

The Baoyi seems to be made from much lower quality parts, the top/bottom shell don't mate up totally evenly and it wouldn't surprise me if it came from the reject pile and was sold then relabeled.
The ZoII seems a bit better quality but lacks lubricant inside it so to me that means it might not trip at the rated current if there is corrosion present.

The Taixi and the TOMZN are both really good quality inside and out -- DiH00l (note that is zero zero verse 'o' 'o') -- is the same parent company as Taixi ...

I checked with a file and all of them have tin plated copper where the bolts go in.... I went deep enough to get through the plating when checking since a lot of the fake bus bars out there are brass that is copper then nickel plated. When plating brass nickel makes a dull pitted finish if you don't first plate it with copper.

I got the Taixi and TOMNZ off AliExpress and the other two came from Temu -- which tracks because a lot of the stuff I have gotten from Temu is marginal quality where from Aliexpress I seem to get exactly what I order.

My preferred brand is the TOMZN black version -- it has the highest AIC of the bunch

 

[Drizzt321]

I've been using these LANGIR double pole, as far as I can tell they're non polarized. I use them mostly as disconnect/secondary protection on my trailer, although since I have portable ground mount solar, it'd be primary protection in that case. It's worked great for me so far.

Amazon.com

Discussion on them in https://diysolarforum.com/threads/langir-breakers-actually-rated-for-500v.70715/

 

[robbob2112]

I've been using these LANGIR double pole, as far as I can tell they're non polarized. I use them mostly as disconnect/secondary protection on my trailer, although since I have portable ground mount solar, it'd be primary protection in that case. It's worked great for me so far.

Amazon.com

Discussion on them in https://diysolarforum.com/threads/langir-breakers-actually-rated-for-500v.70715/

So far as I know this little jewel here indicates it is polarized -- Line on top, load on bottom



Looks like the arc chutes only face up towards the line as well.

 

[agtcovert]

I use several of the Dihool MCCBs in various places - 400A version single pole on both my home and RV system between battery bank bus and Victron power distribution. I've actually tested it in the home system (inadvertently), and the 400A popped on inrush. (Yes, my bad, but...it worked).

These aren't remotely like a standard MCB. They are beefy as hell, and if you get the black case ones for like a main disconnect, you can add a shunt trip and they have around the same interrupting capability as a T-class fuse.

These are my go to for an MCCB.

 

[Andrewr05]

edit: now I can't find where he tested the breakers....edit 2 Nada...I must have dreamed it...I was left with the impression I couldn't rely on these breakers beyond on/off, they wouldn't protect the wires?

He removed the video if I remember correctly because it was something like it turns out that those breakers and the way that it was wired if it was being run with European/International 240V wiring that it was within spec and something something European wiring has their own circuit breakers at each outlet or something like that? So it was actually okay to run it like that?


I don't quite remember, but you didn't dream it.

 

[PVGeezer]

I just ordered a couple of the black ones as well. DHM3Z-320 250A. Going to return the ones I've got since it's looking like they are probably polarized although the documentation is ambiguous. These perform a critical safely function so I don't want to take a chance.

We'll see what the documents say about the black ones when they get here

 

[Drizzt321]

Hrm...

So far as I know this little jewel here indicates it is polarized -- Line on top, load on bottom

View attachment 284416

Looks like the arc chutes only face up towards the line as well.

View attachment 284418

Hrm... I just sent them a message asking for clarification...I hope not.

 

[fuzzmunky415]

He removed the video if I remember correctly because it was something like it turns out that those breakers and the way that it was wired if it was being run with European/International 240V wiring that it was within spec and something something European wiring has their own circuit breakers at each outlet or something like that? So it was actually okay to run it like that?


I don't quite remember, but you didn't dream it.

Ah yes...I recall something mentioned about that, but I also recall him running many A @ 120V thru them well beyond their supposed breaking point.

 

[SparkyJJO]

Hrm...

Hrm... I just sent them a message asking for clarification...I hope not.

If you're using them for your solar strings I see no problem.
I wouldn't be using them for batteries, polarized or not. They don't have the interrupt rating.

 

[PVGeezer]

They don't have the interrupt rating.

Rated for 20kA according to the docs I have, same as blue seas class T fuse.

 

[SparkyJJO]

Rated for 20kA according to the docs I have, same as blue seas class T fuse.

The Dihool MCCBs are (I have some too). He was referring to his LANGIR MCB.

 

[PVGeezer]

The Dihool MCCBs are (I have some too). He was referring to his LANGIR MCB.

Ok gotcha. Too many breakers, too little time...

 

[Drizzt321]

If you're using them for your solar strings I see no problem.
I wouldn't be using them for batteries, polarized or not. They don't have the interrupt rating.

I've got a Class-T at the battery regardless.

 

[robbob2112]

If you're using them for your solar strings I see no problem.
I wouldn't be using them for batteries, polarized or not. They don't have the interrupt rating.

using them for PV with the line/PV panels entering the top they are fine.

 

[Drizzt321]

So far as I know this little jewel here indicates it is polarized -- Line on top, load on bottom

View attachment 284416

Looks like the arc chutes only face up towards the line as well.

View attachment 284418

So they replied, and said that they were unpolarized. But I just realized that they might indeed have a source (e.g. battery) side and load side. I'm asking them about that.

 

[robbob2112]

They can be used between the SCC and the battery no problem --- SCC in on the top, battery at the bottom

What you can't use them for is between the battery and the inverter - if the inverter charges -- if you do all bets are off

 

[PVGeezer]

What you can use them for is between the battery and the inverter - if the inverter charges -- if you do all bets are off

I think you meant can't use them for?