Siemens UL1066, UL 489 Functional overview of the trip unit system, ETU725 ETU727 ETU745

Communication-capable Circuit Breakers

WL Circuit Breaker

Functional overview of the trip unit system

Basic Functions			ETU725	ETU727	ETU745
		Long-time overcurrent protection	✔	✔	✔
		Function can be switched ON/OFF	–	–	–
		Setting range IR = In x …	0.4, 0.45, 0.5, 0.55,	0.4, 0.45, 0.5, 0.55,	0.4, 0.45, 0.5, 0.55, 0.6,
			0.6, 0.65, 0.7, 0.8,	0.6, 0.65, 0.7, 0.8,	0.65, 0.7, 0.8, 0.9, 1
			0.9, 1	0.9, 1
In		Switch-selectable overload protection
	L	(I2t or I4t dependent function)	–	–	✔
		Setting range of time delay class tR at I2t	10s, set at 6 x Ir	10s, set at 6 x Ir	2, 3.5, 5.5, 8, 10,
		(seconds)
		Setting range of time delay tR at I 4t			14, 17, 21, 25, 30
		(seconds)	–	–	1, 2, 3, 4, 5
		Thermal memory	–	–	✔ (via slide switch)
		Phase loss sensitivity	at tsd=20 ms (M)	at tsd=20 ms (M)	at tsd=20 ms (M)
	N	Neutral protection	–	✔	✔
		Function can be switched ON/OFF	–	✔ (via slide switch)	✔ (via slide switch)
		N-conductor setting range IN = In x …	–	1	0.5 … 1
		Short-time delayed overcurrent protection	✔	✔	✔
		Function can be switched ON/OFF	–	–	✔ (via rotary switch)
		Setting range Isd = In x …	1.25, 1.5, 2, 2.5,	1.25, 1.5, 2, 2.5,	1.25, 1.5, 2, 2.5,
			3, 4, 6, 8, 10, 12	3, 4, 6, 8, 10, 12	3, 4, 6, 8, 10, 12
	S	Setting range of time delay tsd, fixed
		(seconds)	0, 0.02 (M), 0.1,	0, 0.02 (M), 0.1,	0.02 (M), 0.1, 0.2,
			0.2, 0.3, 0.4	0.2, 0.3, 0.4	0.3, 0.4, OFF
		Switch-selectable short-time delay
		short-circuit protection
		(I2t dependent function)	– fixed only	– fixed only	✔ (via rotary switch)
		Setting range of time delay tsd at I2t
		(seconds)	–	–	0.1, 0.2, 0.3, 0.4
		Zone Selective Interlocking (ZSI) function	–	–	per CubicleBUS module
		Instantaneous overcurrent protection	✔	✔	✔
		Function can be switched ON/OFF,
	I	Extended Instantaneous Protection
		is enabled when OFF	–	–	✔ (via rotary switch)
		Setting range Ii = In x …	Ii = 0.8 x Icw	Ii = 0.8 x Icw	1.5, 2.2, 3, 4, 6, 8, 10, 12
			50kA max	50kA max	0.8 x Icw = max, OFF=I cw=EIP 1
		Ground fault protection 2	–	✔ (standard)	O (field installable module)
		Trip and alarm function	–	–	✔
		Detection of the ground fault current
		by residual summing method	–	✔	✔
		Detection of the ground fault current
		by direct sensing method	–	–	✔
	G	Setting range of the Ig for trip	–	A, B, C, D, E	A, B, C, D, E
		Setting range of the Ig for alarm	–	–	A, B, C, D, E
		Setting range of the time delay tg
		(seconds)	–	0.1, 0.2, 0.3, 0.4, 0.5	0.1, 0.2, 0.3, 0.4, 0.5
		Switch-selectable
		ground fault protection
		(I2t / fixed)	–	–	✔
		Setting range time delay tg at I2t	–	–	0.1, 0.2, 0.3, 0.4, 0.5
		ZSI ground function	–	–	per CubicleBUS module

1Extended Instantaneous Protection (EIP) allows the WL breaker to be applied at the withstand rating of the breaker with minus 0% tolerance; that means no instantaneous override whatsoever. EIP further enables the circuit breaker to be applied up to the full instantaneous rating of the breaker on systems

where the available fault current exceeds the withstand rating.

2Ground Fault Module cannot be removed after installation.

✔available

–not available O optional

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WL MODBUS Communication and Electronic Accessories • January 2005