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Siemens 5SJ6420-7 — Miniature Circuit Breakers (MCB)

Siemens 5SJ6420-7 SENTRON MCB, 4-Pole C 20A 6kA 400V

MPN5SJ6420-7

Siemens SENTRON 5SJ6 series, miniature circuit breaker, 4-pole, C-curve, 20 A, 6 kA per EN 60898, 400 V AC, 70 mm installation depth.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

5SJ6420-7 — Ratings
ParameterValue
Overvoltage category3

Product details

That C-curve means it holds through mild inrush — think motor starting or transformer energization — and trips fast on a hard short. That's enough for a 20 A feed on 4 mm² or 6 mm² copper, and the big 25 mm² top end lets you land a main feed if this is the panel's incoming breaker. The terminals are sealable — important if the panel sits in a dust-prone environment or needs a tamper tag for warranty. That covers most control rooms and outdoor enclosures in temperate climates.

Sourced through independent distribution channels. The SENTRON series is widely stocked, so lead times tend to be short for this class of part, but we confirm each order individually.

Panel fit and installation

Mounts in any position on standard DIN rail. The 4-pole body takes 4 width units at 18 mm each — 72 mm of rail space total. Vibration-rated to 50 m/s² at 25–150 Hz and 60 m/s² at 10–150 Hz per IEC 60068-2-6, which means it holds up on a machine frame or near rotating equipment without nuisance tripping. The 440 V insulation voltage gives headroom on a 400 V line. Mechanical life is 20 000 switching cycles typical, which is fine for a distribution breaker that sees infrequent manual operation.

Frequently asked questions

Where can I buy the 5SJ6420-7 and how is it quoted?

The 5SJ6420-7 is sourced to order through independent distribution. Submit an RFQ for current pricing and availability — we confirm both at quote time.

What is the wire range for the 5SJ6420-7 terminals?

The terminals accept solid and stranded conductors from 0.75 mm² up to 25 mm². That covers common branch-circuit sizes up to 6 mm² for the 20 A rating, with room for a larger incoming feed if needed.

What breaking capacity does the 5SJ6420-7 have?

It is rated 6 kA per EN 60898 and also 6 kA per IEC 60947-2 at 400 V AC. That is sufficient for most commercial and light industrial distribution boards where the fault level at the panel doesn't exceed 6 kA.

Will the 5SJ6420-7 drop into a panel specified for the 5SL4120-7CC?

No — the 5SL4120-7CC is a 1-pole breaker on an 18 mm footprint, while the 5SJ6420-7 is a 4-pole breaker occupying 72 mm of rail space. They share the SENTRON family and similar terminal specs, but the pole count difference means the panel layout and wiring must be redesigned. These are not drop-in substitutes.

MPN
5SJ6420-7