The current rating on an SPD is how much current it can handle twice without failing.
Surge arrestors work by shunting to ground when activated, so in the case of a Type 2, all that fault current will flow through the main breaker, through the SPD to ground.
If it's high enough, it will trip the breaker. The fault clearing time for a typical thermal magnetic circuit breaker is 4-20 milliseconds even it sees enough current to operate in it's "instananious" region, with is around 5-10X rated current, much slower if it is opperating in its thermal range. You can pull the time-current curve for your equipment to understand this better. The point is, your equipment is already damaged by the time the breaker opens.
The semiconductors in an SPD operate orders of magnitude faster, nano to microseconds.
A.A.Ron
npub1v4…e2y09
2026-09-09 20:05:04 UTC
in reply to nevent1q…dcdw
Author Public Key
npub1v40sr983gxp3x685mgmjvgsxy3t77u7t78ndk9e56truqhsq989q3e2y09Published at
2026-09-09 20:05:04 UTCEvent JSON
{
"id": "0000027934f784501f7580ed567e29e3aaacb93ff4997ea47451df24e8a0069c",
"pubkey": "655f0194f141831368f4da372622062457ef73cbf1e6db1734d2c7c05e0029ca",
"created_at": 1788984304,
"kind": 1,
"tags": [
[
"e",
"0000d1ac3999c5f7363552e2b638df72b95344f7eb00cf82bce7cba8c2b9ae4b",
"wss://relay.wisp.talk/",
"root",
"e2ccf7cf20403f3f2a4a55b328f0de3be38558a7d5f33632fdaaefc726c1c8eb"
],
[
"e",
"00000c0a7789ccce3117e293b327704eee530afd7e87cce3a51decd373e38bee",
"wss://nostr.wine/",
"",
"010df0c948fe9ab54d2cb7ea420ffa08d57958981b6ea68e83aaa7eb2dd3f05a"
],
[
"e",
"a58b947dcc65c2b34a5febd0941dd6decb52941d709ff7142e325178dac03eea",
"wss://freelay.sovbit.host/",
"reply",
"036533caa872376946d4e4fdea4c1a0441eda38ca2d9d9417bb36006cbaabf58"
],
[
"p",
"e2ccf7cf20403f3f2a4a55b328f0de3be38558a7d5f33632fdaaefc726c1c8eb",
"wss://relay.bitcoinpark.com/"
],
[
"p",
"010df0c948fe9ab54d2cb7ea420ffa08d57958981b6ea68e83aaa7eb2dd3f05a",
"wss://nostr.wine/"
],
[
"p",
"036533caa872376946d4e4fdea4c1a0441eda38ca2d9d9417bb36006cbaabf58",
"wss://theforest.nostr1.com/"
],
[
"nonce",
"100cvn",
"21"
]
],
"content": "The current rating on an SPD is how much current it can handle twice without failing.\n\nSurge arrestors work by shunting to ground when activated, so in the case of a Type 2, all that fault current will flow through the main breaker, through the SPD to ground.\n\n If it's high enough, it will trip the breaker. The fault clearing time for a typical thermal magnetic circuit breaker is 4-20 milliseconds even it sees enough current to operate in it's \"instananious\" region, with is around 5-10X rated current, much slower if it is opperating in its thermal range. You can pull the time-current curve for your equipment to understand this better. The point is, your equipment is already damaged by the time the breaker opens.\n\nThe semiconductors in an SPD operate orders of magnitude faster, nano to microseconds.",
"sig": "17d4e7c38275e98237e27e797578ab2ad757b77a224de59ae73bc2996d10a9892171de8ab4922727d34f98f093f1e78f2d95b9992ba730dee457ebf2e8073abc"
}