Just what the title states. The house, located in India, uses old-fangled kitkat fuses. The typical domestic supply here in this part of the world is 250V AC at 50cps. I am in the middle of replacing the fuses with Miniature Circuit Breakers.

MCB appear to receive the line wire from the top connector, the bottom connector being the protected device/s. Is this universal/standard? Does the protected device connect to the top, or bottom of the MCB?

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    Where are you on the planet, and what make and model of circuit breaker are you using? – ThreePhaseEel Feb 12 '17 at 16:13
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    Most panels are fed from the top but not all. When the term MCB is used I think more of a commercial industrial install where the feed phasing is top to bottom, left to right or front to back. Over the years I have found this standard violated and they were installed by licensed electricians and inspected. – Ed Beal Feb 12 '17 at 16:25
  • @ThreePhaseEel: Updated the location. For the second part of your question - my query is whether regardless of make/model; note the words universal/standard in my description. – Everyone Feb 12 '17 at 16:39
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    @Everyone -- it actually depends on what standards the breakers are certified to, but it's easier to look up the make/model and run from there – ThreePhaseEel Feb 12 '17 at 16:44
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    I get that the kitkat fuse is symmetric and the miniature circuit breakers you have in your possession are designed to fit in the same holders and so could go in either way, and you know which end of the fuse holder is line (power in) and which is load (circuit). In the US breakers have a lever and the lever on position is toward the line (bus bar) and off away from the bus bar. Don't these miniature breakers have any instructions. – Jim Stewart Feb 12 '17 at 18:02

Either way around

If the circuit breaker is not marked otherwise, it should be suitable for installation in either configuration -- AFAICT without access to the IEC standards, IEC breakers (MCBs) are just like their UL compatriots in this regard.

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    I can confirm that it is completely acceptable for IEC-style DIN-mount MCBs to be fed from either side. Good practice is to have them all the same, top fed is a little more common, and in larger boards you will find the breakers horizontal with the feeds at the centre and loads at the edges. – Someone Somewhere Oct 27 '18 at 11:40

KITKAT fuses are a very untypical protective device for homes in the USA. By the current regulatory standards renewable over-current devices are not permitted. MCB usually describes the Main Circuit Breaker in a residential electrical distribution panel. The term Miniature Circuit Breaker is normally applied to a din-rail mounted devise used in conjunction with machine wiring or product applications. You should be using a electrical panel approved for residential use listed for the purpose. The installation will require an electrical inspection completed by a certified inspector in your state. Please keep in mind this type of work is not typically done by a novice. In the event the home owner completes the work even with an inspection the owner is responsible / liable if the system does not function properly. This meaning your insurance company is not obligated to cover losses due to fire caused by poor or improper workmanship. If injuries or worse occur there are legal implications and a lawyer per hour will make you wish you hired a qualified electrician.

Regards John J Deery Master Electrician

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    Did you miss the fact that this installation is in India? – Speedy Petey Feb 12 '17 at 22:31
  • DIN-rail mounted Miniature Circuit Breakers (MCBs) are used in most homes in the UK. – RedGrittyBrick Mar 15 '17 at 15:13
  • The OP is in a different country , in my state a home owner or immediate family can do all there electrical no license required. – Ed Beal Jul 14 '17 at 19:00
  • @RedGrittyBrick no hot buses? So you Brits run a wire to both sides of the breaker? Lemme guess. First you have to come through a fuse? ;-) – Harper Jul 14 '17 at 22:15
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    @Harpur. Also see diy.stackexchange.com/a/30154/2815 for fairly typical UK supply-side fuses in external meter box set into outside wall of house (though this 3-phase supply is relatively rare, single phase just has one 100A 415V rated fuse). – RedGrittyBrick Jul 15 '17 at 12:15

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