Fuses vs Circuit Breakers, What's in your Distro?

[JD]

Ok, even after 30 years (and roughly 4000 set-ups & shows) I run into situations that leave me scratching my head.

Keep in mind, in the following paragraph we are NOT talking about a disconnect or a company switch, but the distro that breaks up the circuit into smaller circuits such as 20s and 50s.

Had a house electrician give me a hard time because my distro used circuit breakers! His point was that circuit breakers can jam and if that happens there is noting limiting the current going into the smaller circuits. True. But I don't think I have ever seen a fused distro in use! Once again, I am not talking about the company switch (fused) or a disconnect box (fused), but the actual breakout distro for the smaller circuits. Now, this was not a young guy, but a licensed electrician who has been in the biz since 1972. Anybody ever run into this?

His attention turned onto the sound company who had no protection in their distribution, and later a different electrician came on duty who had no problems with breakers.

[highschooltech]

No, i've never seen a distro with fuses instead of breakers. All the distros that i have used have been breakered. Besides breakers work with magnets the more current that flows through them the stronger the pull. Even if for what ever reason the jammed the breaker would still trip at a certain point, even if it was to late to save the gear.

[zac850]

Never seen a fused distro either. I've only ever seen breakers on the distros and fuses in the switch. Never even heard of a fused distro for that matter.

[derekleffew]

Originally Posted by JD

...Had a house electrician give me a hard time because my distro used circuit breakers!...

You should have asked him what the distribution panel in his house used. Screw-in fuses are becoming rarer each day, so unless he lived in a house older than fifty years, a very good chance he had breakers in his own home. I think he must have previously read your signature, and therefore didn't trust you.

[SteveB]

I'm thinkin' one of the fuses in his head was blown.

You cannot even BUY a fused distro., and haven't been able to in at least 30 years, excepting some 3rd world countries - like Australia or New Zealand or some place like that (grin).

Nut job.

Steve B.

[porkchop]

A fused distro would anger me, I'm so happy this is not actually something you see. Even before thinking of testing connections that are misbehaving and having to change the fuse every time it pops, my distro's sit on the grid imagine having to change a little fuse while 35 ft. over head. No thank you, the load (aka the lights) can be in charge of their own fused over current protection I like my distros with breakers

[ship]

Hmm, just made a 24way 208v power distro with Emergency stop system currently out on tour with some large rock tour and didn’t get anything other than complements for it. It only had one fuse in it and it was in-line for the LED Little Lights and that was only out of laziness in doing that instead of a breaker. Just change a few things or re-tap a transformer and it would even tour Europe sufficiently. This much less a 15KVA 208v Delta to 240/416V wye transformer also using breakers in the past few weeks without anyone citing the other than well done. (Any wonder that I have been less than active in the last few weeks?)

Hmm, circuit breakers, I would hope one is not to be using plug fuses as they could be non-complaint with a stick finger into larger than 1/4" hole type of way. Given a plug fuse AC distro (not even counting such a thing in finding than screwing in such such a replacement fuse in the dark) or finding the replacements, how would one get around that live center of the opening type question of being zapped in a Darwin type way we try to over protect against?

Hmm, for some reason the photos didn't download even if resized.

Assuming this person was all for other than screw in plug fuses, and instead up for something for individual circuits that are smaller such as using a FRN type, why? As licenced electrician wouldn’t that invalidate the current code concepts of tied especially dual phase breakers? Not aware of dual fuses that will cut off power to more than one leg of power should they blow. Even for single phase circuits, gotta find the spare fuses and get them in quickly, this much less while fuses are simple blow, you can dial in your say thermal magnetic fuses for similar coverage.

What happens if given fuses and you have two phase gear if one phase blows but the other didn’t? Isn’t that a bit dangerous and specifically to be prevented? Jamming of circuit breakers I would assume he was thinking with dual phase handle tied but not internal trip breakers which can if not properly done jam. More realistically they will jam in the off position - personal experience with that by way of flexibilty of that in not being able to turn it on but still it could jam on as a concept, or for multi-pole breakers a single pole in theory in blowing could not be sufficient to trip the rest. How does the individual circuit breaker work better than persay not a tied breaker but internal/external bridged breaker for controlling two phase circuits? Single breaker trips in exposing an open or even floating return path in concept which could get very dangerous in concept of what he would seek to protect against.

Most distros these days are two or more phase and even if not are normally circuit breakers and UL listed plus engineered gear from very reputable companies that sit on the NEC board. Not aware of any fused breaker distros on the market these days. Would just love to pluck from his mind that while in general fuses are better overall for simplicity, how dependant on what type of breaker you use, they are superior especially given what fuse verses breaker type is used. This much less how he thinks it’s better and what gear he recommends and who is using it. Just love to talk with confused people in plucking out info from them that is often useful to know even if often years out of date.

Nope... even this past week in making a CamLoc to 32A6h 3P+N+G adaptor and using a 32A three pole circuit breaker with the necessitated indicator lights and plywood backer on it, never once thought about using fuses for it. This other things made in the past couple of weeks or other than code compliance for its application.

Believe you just met the “grumpy old man of the theater”. Congrats. Learn what you can from him and take what you can from what you can for where it can be useful, otherwise just often they just need some time to talk in being heard.

Would love to hear his thoughts about the new four pole breakers - one with the 50% neutral breaker that breaks the circuit if it detects an un-balanced load of over 50% on the neutral, this or the various GFCI and other new types of breakers. Just pricing out main breakers for my 48way E-Stop power supplies recently, amazing the trip ratios available much less the options and features available.

[TimMiller]

I would never put fuses in a distro. Heck, at work we have shy'd away from installing fuses in control panels and started using breakers. Only thing i use fuses for are for big 3 ph motors used for industrial applications, and then if they were to blow a fuse, they would over load the other two legs and trip the over load protection. One new type of breaker i have seen has built in under voltage protection. I am thinking about using these in our generators, they trip the breaker once the voltage hits around 80V. Which if the generator were to fail for any reason it would shut the breaker off, so the gear does not completely brown out. Once automation directs website is back up i will post a link to the breakers i am talking about. What do you think ship?

[Chris15]

Hmmm.. fused distro... sounds rather non code compliant at least on this lil island...

Ship et al please do correct me if I'm wrong but last time I checked, breakers can still disconnect the load even with the handle locked in the on position - an arrangement used sometimes for supplies to fire alarms, security alarms etc.

[TimMiller]

Breakers can shut off a load even with the handle locked to the on position. That is why you must turn the breaker to off then back to on to reset it. It will not allow you to just push it back to on. Using fuses is not against the NEC, its just completely not pratical.