Comments on: DC circuit breakers https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/ All about electronics and circuit design Sat, 25 Apr 2026 16:50:59 +0000 hourly 1 http://wordpress.org/?v=3.9.14 By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-3/#comment-1862025 Wed, 17 Sep 2025 19:41:36 +0000 http://www.epanorama.net/blog/?p=20225#comment-1862025 Mikäli tarkoitat automaattisulakkeella tavanomaista johdonsuojakatkaisijaa, se toimii taysin samalla lailla 230 V:n ja 12 V:n vaihtojänniteverkoissa.

Tasavirralla johdonsuojakatkaisijan toiminta poikkeaa vaihtovirran toiminnasta:
- johdonsuojakatkaisijan toimintajännite rajoittuu dc:llä yleensä n. 70 V:n nurkille. Isompia jännitteitä 1-napainen jsk ei kykene luotettavasti erottamaan vaan saattaa toimiessaan hitsaantua kiinni.
- johdonsuojakatkaisijan oikosulkuvirran katkaisukyky on dc:llä matalampi kuin ac:llä
- johdonsuojakatkaisijan laukaisukäyrä, ja erityisesti sen magneettinen laukaisuosuus, ovat erilaiset dc:llä ja ac:llä.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-3/#comment-1859642 Wed, 13 Aug 2025 16:30:53 +0000 http://www.epanorama.net/blog/?p=20225#comment-1859642 No, you can’t.

Design Differences: DC and AC currents behave very differently. AC current alternates direction and passes through zero many times per second, making it easier for AC breakers to interrupt faults. DC flows continuously in one direction without zero-crossings, so DC breakers need special features (like bigger gaps, arc chutes, or magnetic blowouts) to extinguish powerful arcs.

Arc Interruption: AC circuit breakers rely on the current dropping to zero (the “zero point”) during each cycle to safely extinguish the arc. DC does not naturally have these zero points, so when a fault occurs, DC arc is much harder to break, requiring a different internal mechanism.

Trip Characteristics: The thermal and magnetic mechanisms inside AC and DC breakers are calibrated for their respective currents. Using the wrong type results in unreliable protection and nuisance tripping or even failure to disconnect during a fault.

Risks of Misusing Breakers
Overheating and Fire: Using a DC breaker for AC or an AC breaker for DC may result in persistent arcing, overheating, excessive wear, device failure, and even fire.

Reduced Protection: Breakers may fail to properly interrupt fault currents, creating serious electrical hazards.

Illegal and Unsafe: Electrical codes and manufacturers universally warn against interchanging AC and DC breakers for safety and legal reasons.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-3/#comment-1850731 Sun, 06 Apr 2025 20:42:11 +0000 http://www.epanorama.net/blog/?p=20225#comment-1850731 https://www.se.com/fi/fi/product/A9N61508/c60h-dc-johdonsuojakatkaisija-1p-c-10a/

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-3/#comment-1850730 Sun, 06 Apr 2025 20:40:50 +0000 http://www.epanorama.net/blog/?p=20225#comment-1850730 The circuit breakers from Biltema do not seem to be rated for DC use
https://www.biltema.fi/rakentaminen/sahkoasennustarvikkeet/tarvikkeet-sahkokeskuksiin/automaattivarokkeet-1-napainen-16-a-2000050157
https://docs.biltema.com/v2/documents/file/fi/15b91d06-099f-463a-a471-353af2ea44a5
https://www.biltema.fi/rakentaminen/sahkoasennustarvikkeet/tarvikkeet-sahkokeskuksiin/automaattivarokkeet-1-napainen-10-a-2000050159
https://www.manua.ls/biltema/44-0011/manual?p=8

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-2/#comment-1849477 Wed, 26 Mar 2025 19:33:21 +0000 http://www.epanorama.net/blog/?p=20225#comment-1849477 DC Circuit Breaker 12v 24v 36v 48v 60v 72v 110v 120v 3A 6A 10A 16A 20A 25A 32A 40A 50A 63A Circuit Overprotector (Color : 1P, Size : 3A)
https://www.amazon.com/Circuit-Breaker-110v-120v-Overprotector/dp/B0CSWR24CC?th=1

Product details

Package Dimensions ‏ : ‎ 1.18 x 0.79 x 0.39 inches; 7.05 ounces
Item model number ‏ : ‎ SAYOBO
Department ‏ : ‎ Unisex Adult
Date First Available ‏ : ‎ January 20, 2024
Manufacturer ‏ : ‎ SAYOBO
ASIN ‏ : ‎ B0CSWR24CC

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-2/#comment-1849476 Wed, 26 Mar 2025 19:32:40 +0000 http://www.epanorama.net/blog/?p=20225#comment-1849476 DC Circuit Breakers
70A 12V/24V/48V Automatic over-current DC circuit breaker / switch
https://www.photonicuniverse.com/en/catalog/full/904-70A-12V24V48V-Automatic-over-current-DC-circuit-breaker–switch.html

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-2/#comment-1849475 Wed, 26 Mar 2025 19:32:14 +0000 http://www.epanorama.net/blog/?p=20225#comment-1849475 https://www.grainger.com/category/electrical/fuses-circuit-breakers-safety-switches/circuit-breakers-panelboards-load-centers/circuit-breakers-accessories/din-rail-mount-miniature-circuit-breakers?attrs=DC+Voltage+Rating%7C48V+DC&filters=attrs

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-2/#comment-1849470 Wed, 26 Mar 2025 18:42:26 +0000 http://www.epanorama.net/blog/?p=20225#comment-1849470 ABB #SU201M-K6
Circuit Breaker, Miniature; 1P; 277V AC 48V DC; 6A
https://www.carltonbates.com/Electrical-and-Power-Distribution/Circuit-Breakers/Breakers-Small-Frame/Standard-Circuit-Breakers/ABB/Circuit-Breaker-Miniature-1P-277V-AC-48V-DC-6A/SU201M-K6/p/01677993006-1

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-2/#comment-1849466 Wed, 26 Mar 2025 18:41:06 +0000 http://www.epanorama.net/blog/?p=20225#comment-1849466 ABB S201MC16UC MCB 10kA 1P 16A 220VDC C CURVE INDUSTRIAL
https://www.ipd.com.au/mcb-1-pole-16a-10ka-uc-c-curve-s201mc16uc

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2013/06/27/dc-circuit-breakers/comment-page-2/#comment-1849465 Wed, 26 Mar 2025 18:40:28 +0000 http://www.epanorama.net/blog/?p=20225#comment-1849465 ABB S202 C4 circuit breaker 4kV 2A 50/60Hz 110V DC 2-pole AC/DC 3.6W
https://industrie-24-de.myshopify.com/products/abb-s202-c4-sicherungsschalter-4kv-2a-50-60hz-110v-dc-2polig-ac-dc-3-6w?srsltid=AfmBOooeDNmJLxMe02DYdh_nUtWZWHHJ_Pgo_xxzYiQdS45NB85f8cdq&shpxid=cf543765-e01e-4542-b1bc-f38565210c95

Manufacturer: ABB
Type/Manufacturer number: S202 C4
Product type: fuse switch
Condition: used

EAN: 4016779523400
Input voltage type: AC/DC
Rated impulse withstand voltage: 4kV
Rated current: 2A
Rated frequency: 50/60Hz
Power dissipation: 3.6W
Feed : Any
Number of poles: 2 poles
Installation position: Any
Ambient operating temperature: -25 … +55 °C
Ambient storage temperature: -40 … +70 °C
Protection class: IP20
Operating voltage max: 110V DC
Width: 35mm
Height: 88mm
Depth : 69mm

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