Using Single-Pole Switch for 24V DC Network: Legrand Overcurrent Circuit Breaker S301

Question

Is it possible to use such a single-pole switch for 24V DC network:

http://meskon.pl/s301-wylacznik-nadpradowy-legrand-p-994.htm

The rated voltage is 230/400 50Hz, hence the doubt whether such a switch is suitable for a 24V DC network.
Are there special DC circuit breakers?

Anonymous · Accepted Answer

I would not compare these switching currents so directly, especially since in the case of direct current they do not indicate compliance with the standard, and as you can see in the previous picture, there may be differences. Please note the voltages Un .
For the sake of curiosity, I can say that I met with eSka 6A with infinitely great switching capacity. And they achieved this by adding additional resistance. Such protections with higher resistance are used only in switchgears, transformer stations, etc. to supply auxiliary and lighting circuits in these facilities.
And maybe eSki DC for comparison:

Akrzy74 · Answer

The link is not working - please fix it. There are special overcurrent circuit breakers marked DC for DC circuits. E.g. FAZ-C25/1-DC by MOELLER

Łukasz-O · Answer

Looking just at the quick in the Legrand catalog, the S 300 series is also suitable for DC.

niutat · Answer

Especially since it's only 24V.

kasjo · Answer

Don't the ess used in 220V circuits provide full DC protection? Is there any standard that requires the use of such protection in DC circuits? I'm asking out of curiosity, because to be honest it's the first time I hear about it (I have to look at the machines in the company) I mean 24VDC

Anonymous · Answer

Which the more. When circuit breakers designed for higher voltage are used in installations with lower voltage, we can expect higher overvoltages during the breaking time.

niutat · Answer

You haven't convinced me, my friend WojcikW you can explain it.

HeSz · Answer

Legrand's IDS S 302 overcurrent circuit breakers with characteristic D can be used in DC circuits. More information in the Legrand e-catalogue. Regards.

chudy0283 · Answer

Here is the list of overcurrent circuit breakers from TME:

http://www.tme.eu/overcurrent-breaker-series-cls6-16a-1-pole-c/arts/pl/a23/cls6-b6.htm

They do not offer something for 24V and if something is not on offer, maybe these 230V/400V switches can be used for direct current??

What about 24V AC or 110V AC circuits??

niutat · Answer

As for the AC circuits, it is obviously easier to extinguish the arc with a lower voltage (although colleague WojcikW has some new theories) and such switches are commonly used in machine tools in control, lighting or signaling circuits. As for DC, in circuits up to 30V I also saw factory-installed ordinary AC switches.

Anonymous · Answer

Exactly what you wrote. Fast arc extinction results in more overvoltage. In practice, the overvoltage value expressed in [V] will be the same as in the 230V network, but the lower voltage installation does not always provide for this.

niutat · Answer

You still did not convince me, if such overvoltages occurred, they would support the burning arc and thus extinguish themselves. In addition, such switches are mounted as I wrote earlier, so there are probably no major problems with it.

chudy0283 · Answer

I'm more interested in whether, for example, such a single Eska B10 will work at DC 10A, are the current characteristics the same then?

Anonymous · Answer

And I'm not going to. Skinny0283, there is no definite answer. The characteristics for the thermal release (overload trip) will be the same. Different for the electromagnetic release (switches off short circuits). Whether it is suitable depends on the installation. The short-circuit power at the place where the protection is installed has the greatest role. So, describe the installation a bit, the power of the receivers and, above all, describe the power source.

Ryszard49 · Answer

skinny0283 he wrote: I was testing with 10B and 40V DC. With a load of 20A, the fuse did not work, I ended the test because I had no way to increase the load in the circuit. It worked when it was short-circuited.

chudy0283 · Answer

We are expanding the device, we have one big 24V DC power supply (I don't remember which one because I'm at home now) and we want to power 12 reed switches from it, and we want to provide some current protection to protect this power supply against short circuit, overload in this expanded part of the device. I saw such solutions in the previous company (individual sections of sensors on the machine protected by "eski"), but I do not remember what type of "eski" it was.

Added after 8 [minutes]:

Ryszard49 wrote:

I was testing with 10B and 40V DC. With a load of 20A, the fuse did not work, I ended the test because I had no way to increase the load in the circuit. It worked when it was short-circuited.

Hmm, so it only protects us against a short circuit ... and if you want to give an "eska", you need to find one for DC current. Or you can just give a fuse ....

Aleksander_01 · Answer

If you keep it like that for half an hour it should work. Gentlemen, after all, the fuse does not see the voltage, the phase shift only sees the current (effective) value. As for the voltage - the manufacturer guarantees certain extinction of the arc up to the value of this voltage. For example, an American 115 V/10 A fuse is not recommended to be installed in our installation because it can pull the arc. On the other hand, European ones can be installed for their installation. Only which American will buy a fuse three times more expensive (hehe). And more conclusions - calmly and without fear, overcurrent fuses, e.g. S191 B10, can be mounted to DC installations up to the voltage value given on the fuse. After all, that's what it was made for.

HeSz · Answer

Gentlemen.
Most manufacturers do not recommend the use of the so-called "eSek" in DC circuits, due to too short times of contact separation. With a relatively small insulating gap, the arc formed when separating the contacts will burn them "beautifully". The durability of such protection will be negligible. Only "Legrand" allows the use of (mentioned earlier) overcurrent circuit breakers of the S302 type, but with the D characteristic, for use in DC circuits up to 24 V.
Higher voltages require the use of so-called "high-speed circuit breakers" as the executive element of the protection.
Regards.

Anonymous · Answer

Nonsense. I completely agree with HeSz. Completely different conditions are when we switch off (interrupt) direct current. I would like to add that the characteristics of the protection change, and more precisely - at a different value, the electromagnetic releases will work.

niutat · Answer

As for switching off DC, of course there are bigger problems with it, especially if the load is inductive (tables, couplings, etc.). for comparison, I will give data from the TSM-2 contactor for 220V AC max. switched off power is 7.5kW but for DC it is only 3.5kW. As for the characteristics, in my opinion, with direct current, the protection will work at a lower current value.

HeSz · Answer

The contactor has a gap - approximately twice that of a relay or trip unit with the same armature movement!

niutat · Answer

Not only that, contactors usually have series contacts, I just gave an example for comparison.

eva54 · Answer

Gentlemen, having in front of you a diagram of a CNC machine where the voltage of DC 24V is used. On the secondary side of the power supply, depending on the load, overcurrent switches are used, e.g. FAZ-C10/2 by MOELLER.

Aleksander_01 · Answer

Working in the industry, I had contact with modern machines of German and French production (machine year 2000 to 2002), and in these machines on the primary side (230, 400 V) identical fuses were used as on the secondary side (24 VDC).
But we know that countries such as Germany or France are total backwardness and do not know about the variable characteristics of fuses, I also only learned today from WojcikW. Of course, the fuse distinguishes the phase shift (I wonder what else it can do).
As many fuses as there are types of electricity.

Anonymous · Answer

Aleksander_01 saw something, but he doesn't know what, anyway identical on the 230V AC and 24V DC side. I don't know why Aleksander_01 doesn't read earlier posts and then jumps out like Filip from hemp - what he didn't see while working in the industry. If he saw the fuse-links, the manufacturer specifies that they can work in a DC installation (for DC, the maximum operating voltage is usually lower than for AC). If he saw installation switches, it was written that ordinary eSek operation up to 24V DC voltage is allowed. In general, ordinary eSek cannot be used in DC installations, however, in some low-power sources, the sources will work properly and such application in practice cannot be ruled out. If ordinary eSki could be used in DC installations, the manufacturer would not fail to write it. There would also be no need to produce eSek DC.

Aleksander_01 · Answer

To WojcikW:
You explained it very nicely.
The same (same type) fuses were used for 230 VAC and 24 VDC, of course they were fuses and not fuses.
Fusible plugs have one indisputable advantage - they perfectly extinguish the arc (for constant or variable).

I've worked with machines where the controls were 110V, but they were machines from the 70's and all fuses were blown. Fact - I have not encountered DC voltages above 24 V (except battery trolleys - tubular fuses).

Anonymous · Answer

From the Schneider Electric catalog it can be concluded that there are special eSki for direct current DC:

However, regular eSki can be used for DC. Please look at the short-circuit breaking capacity, it is also specified for DC. For a single-pole circuit breaker, the voltage is Un = 24/28V, for a four-pole circuit-breaker Un = 250V.

chudy0283 · Answer

It seems that it differs only in breaking capacity and near In for AC and DC they will work the same.

The same applies to fuses:

http://www.automatykab2b.pl/content/view/915/33/

However, here the breaking capacity is lower for DC current, in contrast to electromagnetic circuit breakers

HeSz · Answer

I don't quite understand how you define breaking capacity. Please explain more.

Using Single-Pole Switch for 24V DC Network: Legrand Overcurrent Circuit Breaker S301

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