Circuit protection
Circuit protection
(OP)
Hi sounds like a simple question. is ok to use a switch rated at 16a in a circuit protected by a 16 a breaker, or does the switch rating need to be under that of the breaker, the expected load is only 6A





RE: Circuit protection
RE: Circuit protection
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Circuit protection
RE: Circuit protection
I think there's at least one exception in 7671 but unless you're going to take advantage of it dozens of times over I don't think you'd see any saving. Most lighting switches (for example) are designed with a current rating of 10A for use a a circuit with a 10A breaker or fuse because almost every doemstic / commercial / light industrial lighting circuit will use either a 6A or 10A breaker or fuse.
Can you put the question a bit more in context?
RE: Circuit protection
Generally i just wanted clarification that i was not making a fuss when i insist that circuit "accessories" such as relays and switches are protected by a device rated either equal to or lower than the current carrying capabilities of the circuit it protects. I know it is true for cables just couldnt find any regulations that backed up my approach when it came to that actual control devices
RE: Circuit protection
RE: Circuit protection
FWIW, it's usually easier to find rotary switches with decent ratings rather than rockers. You're looking for AC23 rating for a motor switch. Do you have to use a rocker switch?
RE: Circuit protection
With respect to my wider question, for future reference if I am making alterations in electrical panels replacing components etc it has just highlighted the need for me to clear things up a little.
Do the regulations in BS7671 only apply to supply installations, obviously when designing wiring inside an electrical panel etc you would try to select cables according to their expected load its just that do you need to rate components and cables inside a panel to the size of the breaker that protects them without exception?
To clarify things i will give you a couple of examples these are not specific examples but just highlight my point
Installing a relay in a panel with its coil wired in parallel across an incoming supply cable. the relay being used to drive a light that indicates the presence of supply. The supply cables may be say 6mm so protected b say a 32A breaker, do the coil connections of the relay need to be as big so that they are adequately protected or is this overkill
A phase rotation relay as above connected in line with the main phases, do the sensing cables need to be fused ?
A proximity connected into a control circuit protected by a 4A breaker with a rated switching current of 200mA
I hope from these questions you can see what i am trying to establish, its not something i have thought about much before. I am sure i have come across installations where situations similar to that described above exist.
what is the common practise?
RE: Circuit protection