Tabulated functional capabilities of LV switchgear

After having studied the basic functions of LV switchgear (Figure H1) and the different components of switchgear,Figure H22 summarizes the capabilities of the various components to perform the basic functions.

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Switchgear item	Isolation	Control				Electrical protection
		Functional	Emergency switching	Emergency stop (mechanical)	Switching for mechanical maintenance	Overload	Short-circuit	Electric shock
Isolator (or disconnector)(4)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Switch(5)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Residual device (RCCB)(5)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]			[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Switch- disconnector	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Contactor		[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (3)
Remote control switch		[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)		[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Fuse	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]					[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Circuit breaker		[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Circuit-breaker disconnector(5)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Residual and overcurrent circuit-breaker (RCBO)(5)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math] (1) (2)	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]	[math]\displaystyle{ \color{RoyalBlue} \blacksquare }[/math]
Point of installation (general principle)	Origin of each circuit	All points where,for operational reasons it may be necessary to stop the process	In general at the incoming circuit to every distribution board	At the supply point to each machine and/or on the machine concerned	At the supply point to each machine	Origin of each circuit	Origin of each circuit	Origin of circuits where the earthing system is appropriate TN-S, IT, TT

(1) Where cut-off of all active conductors is provided
(2) It may be necessary to maintain supply to a braking system
(3) If it is associated with a thermal relay (the combination is commonly referred to as a “discontactor”)
(4) In certain countries a disconnector with visible contacts is mandatory at the origin of a LV installation supplied directly from a MV/LV transformer
(5) Certain items of switchgear are suitable for isolation duties (e.g. RCCBs according to IEC 61008) without being explicitly marked as such

Fig. H22: Functions fulfilled by different items of switchgear