Selecting Fuses B or C for Carpentry Shop: Saw Motor & Differential Ratings

Question

Hello I have a question, what are the rules for selecting fuses, for which receivers B is selected and for which C? I mean single and three-phase current; my second question is about differentials, when do we use a 30mA differential and when a 300mA differential? the questions arise from my...

bandzior2 · Answer

Only 30mA residual current devices are used in domestic installations. 300mA is rather used on construction sites.

alfaam · Answer

Motor devices, due to the high starting current, are secured with C type protections or preferably with motorized. In this case, C16 should run (no load starting), it would be more reliable on C20, but you must check whether the conditions for quick shutdown are met.
Suggesting C16 is due to my reluctance to oversize security, and you can always replace it with larger ones if it does not work.
The 300mA differential serves only as "fire protection" and not against electric shock. Apply 30mA and ask the designer to verify the design, the B16 has definitely got it wrong with this one.

and61 · Answer

type B- from 3 In to 5In, type C from 5In to 10In, type D- from 10In to 20In

In is the rated current of the circuit breaker
type B is used in residential and industrial installations
typeC protection of electrical circuits of receivers such as motors, transformers
Type D protects loads characterized by a very high inrush current
Protection against electric shock - differential devices with a current of 10mA, 30mA
Differentials with a tripping current of 300mA-500mA are used as fire protection

bioforge2008 · Answer

well, I can see that I was right that something was wrong; I put this project together with a description and ask for any comments what and how should be changed; Diagram: Description:

alfaam · Answer

Old-fashioned designer
so fast it's control off. P. Fire. outside, in front of the entrance, entrance in a visible place, one is enough, but give two or even three, it all depends on the development. Certainly I would not use it indoors, it may endanger the safety of employees.
APU, I don't know, offers one of the compact circuit breakers with an undervoltage coil, the more that the protectors need to be protected.
Luminaires with electronic ballast or break indoors to 3f switched on simultaneously. Workstation lighting as much as possible.
30mA differentials
5x10 at 7.5kW a bit much but depends on the arrangement etc and may be ok.

bioforge2008 · Answer

exactly, old date designer and for this machine with a total power of 17Kw, I just need a C32 protection and a 5x16 cable? or maybe 5x10? the distance from the switchgear will be up to 5 m; a few more questions: -differentials all the same? Is it possible to give different ones, because I have two c25 and c40, so I think I could hook up machines and smaller engines to them; - how many machines for one differential? -How many wires are needed from the fire switch to the button? because I have not dealt with it and I am not very familiar with how it works? -this joining machines with a rope is probably an exaggeration? because somehow I can't imagine it

alfaam · Answer

The 5x10 cable is definitely enough, the protection must be considered individually, mode of operation, nature, etc. Added after 2 [minutes]: you are an investor or an electrician because I don't know anymore

bioforge2008 · Answer

I am an investor but due to the fact that my electrician friend has not sober for two weeks, I have to get interested in the subject myself and at least do some shopping for what I need, pull the cables, etc., and call a specialist to connect the switchgear;

alfaam · Answer

that's screwed up I would, however, wait until he sober up, or look for another friend

Selecting Fuses B or C for Carpentry Shop: Saw Motor & Differential Ratings

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