a switch before the breaker ?

[lucaperazzolli]

Hi,

I need to explain to a friend of mine (who is building a rv6) that he's doing wrong but I need some help.

He says that if he put a Switch near a CB (connected with a copper bar) he is safe.

Manual says not (for me is enough) but why not ? Waiting for opinions ...

Thanks in advance

[flion]

Well, I'm not an expert but as I understand it: not only does the CB protect the wiring in a circuit, it also protects the buss from a short in the wiring. In most cases, such a short would cure itself pretty quickly (and dramatically) even without a CB but your friend may actually defeat even that level of protection. If the switch or the bar between the switch and CB shorts, all the current will be driven through there; even if the CB tripped it wouldn't break the short. If the switch manages to withstand the current it will doubtless produce tremendous heat and the rest of the buss will be starved. Even if it doesn't, it will still probably fail even more dramatically than burning wire.

Your friend may feel that nothing could ever short the switch or copper bar to ground but then a lot of people have suffered from things that could never happen.