Siemens SENTRON User manual

SENTRON
Technology primer
Residual Current
Protective Devices

Preface
Whether for protecting, switching, monitoring or measuring – low-voltage
circuit protection devices from Siemens perform a wide range of functions
for all applications in the area of electrical installation technology. They
are suitable for use in residential buildings, non-residential buildings or
industrial applications and thus allow you to maintain control over all
electrical circuits.
This is especially important when it comes to selecting and installing the
appropriate residual current protective device. With this primer, we provide
you with a simple tool for perfectly adapting the respective residual
current protective device to the requirements of the electrical installation
in question. Apart from general information on residual current protective
devices, it contains important details regarding installation and use. You
can therefore be assured that you will always choose the right device.

1 Overview 6
2 Introduction 8
3 Protection through residual current protective devices 8
3.1 Additional protection
(previously „Protection against direct contact“) with IΔn ≤ 30 mA 9
3.2 Fault protection (protection against indirect contact) 12
3.3 Fire protection 13
4 Residual current protective devices 14
4.1 Types of residual current protective devices 14
4.1.1 Type AC 16
4.1.2 Type A 16
4.1.3 Type F 16
4.1.4 Type B 16
4.1.5 Type B+ 17
4.2 Classification of residual current protective devices 17
4.3 Basic design and method of operation 19
4.3.1 Type A RCCB 19
4.3.2 SIQUENCE universal current-sensitive RCCB Type B and Type B+ 21
4.4 Features and application areas 22
4.4.1 RCCB 22
4.4.2 RCBO (Type AC/Type A, Type F) 23
4.4.3 SIQUENCE universal current-sensitive RCCB Type B and Type B+ 26
4.4.4 SIQUENCE universal current-sensitive RCBO Type B und Type B+ 30
4.4.5 RC units for installation on miniature circuit breakers 31
4.4.6 SIGRES RCCB (for harsh ambient conditions) 31
4.4.7 Type
Ksuper-resistant 32
4.4.8 Type
Sselective 34
4.4.9 Versions for 50 to 400 Hz 35
4.4.10 Versions for 500 V operational voltage 35
4.4.11 Residual current operated circuit breaker with N-connection
on the left side 35
4.5 Additional components for residual current operated
circuit breakers 36
4.5.1 Remote controlled operating mechanism (RC) 36
Contents

4.5.2 Auxiliary switch 37
4.5.3 Additional components 37
5 Notes on installation and use 38
5.1 General notes 38
5.1.1 Selection of protective devices 38
5.1.2 Use of residual current protective devices 40
5.2 Choosing the right residual current protective device 42
5.2.1 Type A, Type F or Type B/ Typ B+? 43
5.2.2 What protection goal must be achieved? 43
5.2.3 What electrical interference occurs and how is it handled? 44
5.2.3.1 Leakage currents 44
5.2.3.2 High load currents 45
5.2.3.3 Overvoltages and surge current load 46
5.3 Special features regarding the use of SIQUENCE universal
current-sensitive residual current protective devices
(Type B and Type B+) 47
5.3.1 Applications 47
5.3.2 Residual currents at different fault locations, with a frequency
converter (FC) as an example 47
5.3.3 Configuration 52
5.3.4 Causes of excessive leakage currents and possibilities of
reducing them 53
5.4 Back-up protection 55
5.5 Protection against thermal overload 57
5.6 Troubleshooting 58
5.7 4-pole residual current operated circuit breakers in a
3-pole network 59
6 Residual current monitoring devices (RCM) 59
7 Outlook 61
8 Source specified 62
9 Appendix 63
10 List of figures and tables 74

6
Overview
Residual current operated circuit
breaker (RCCB)
SIQUENCE residual current
operated circuit breaker (RCCB)
SIQUENCE residual current operated
circuit breaker with overcurrent
protector (RCBO)
5SM3 / 5SV
• Type AC, Type A and Type F
•
I
n= 16 … 125 A
•
I
∆n = 10 mA … 1 A
• 2-pole (1+N) and 4-pole (3+N)
• N connection at left and right
• SIGRES for harsh ambient
conditions
• Version Kand S
• 500 V version
• 50 … 400 Hz version
5SM3
• Type B, Type B+
•
I
n = 16 … 80 A
•
I
∆n = 30, 300 and 500 mA
• 2-poe (1+N) and 4-pole (3+N)
• Version Kand S
• including SIGRES functionality
5SU1
• Type B, Type B+
•
I
n = 100 ... 125 A
•
I
∆n = 30, 300 mA and 1A
• 4-pole
• Circuit breaker characteristic
C and D
• Rated switching capacity 10 kA
• Version Kand S
1. Overview

7
RC unit for combination with a
miniature circuit breaker
RCBOs; combination units
Residual current monitoring
devices (RCM)
5SM2
• For mounting on a miniature
circuit breaker
• Combined electric shock and
line protection
• Type AC, Type A and Type F
•
I
n = 0.3 … 100 A
•
I
∆n = 10 mA … 1 A
• 2-, 3- and 4-pole
• Version Kand S
5SU1
• Combined electric shock and
line protection
• Type AC, Type A and Type F
•
I
n = 6 … 40 A
•
I
∆n = 10 … 300 mA
• Circuit breaker characteristic B and C
• Rated switching capacity 4.5 kA,
6 kA and 10 kA
• 1+N-pole, 2-pole
• N connection at right and left
5SV8
• Residual current monitoring
• Type AC and Type A
•
I
∆n = 0.03 ... 30 A
• Response time 0.02 ... 10 s
• Summation current transformer
20 ... 210 mm

8
Introduction
2. Introduction
When dealing with electricity, safety has top priority. Every electrician must be
particularly conscientious when safety is concerned and must apply the required
protective measures correctly. In consumer’s installations, residual current pro-
tective devices must be given unreserved preference over alternative protective
devices.
In addition to fault protection (protection in cases of indirect contact), residual
current protective devices with rated residual currents up to 30 mA also provide
“additional protection” in cases of direct contact. Fires caused by ground-fault
currents can also be prevented at a very early stage.
In many cases, the DIN VDE standards require the use of residual current protec-
tive devices. Electricians should therefore make sure that they are fully informed
about residual current protective devices.
In addition to information on the protective effect of residual current protective
devices, an understanding of how the devices function is also conveyed. In order
to optimally adapt the use of residual current protective devices to the require-
ments of the electrical installation, the functionality of the different versions of
residual current protective devices is discussed and the user is given practical
installation and application tips.
3. Protection through residual current protective devices
The basic prerequisite for use of a residual current protective device in order to
automatically disconnect the power supply as a protective measure is that an
appropriately grounded protective conductor is connected to the system com-
ponents and equipment to be protected. Current can then pass through a human
body only when two faults occur (interruption of the PE conductor in addition to a
fault in the insulation) or when there is unintentional contact between live parts.

9
Protection through residual current protective devices
3.1 Additional protection (previously „Protection against direct contact“)
with IΔn≤30mA
Additional protection is understood to mean protection which takes effect if there
is direct contact of a human body with a part normally live during operation in
the event of basic and/or fault protection failing. When a human body touches
live parts, two resistors connected in series determine the intensity of the  owing
current – the internal resistance of the human body Rmand the transfer resistance
of the location Rst ( gure1).
Direct contact
In² 30 mA
RBRst
Rm
IM
Figure 1: Protection against direct contact
In order to consider the accident properly, the worst case scenario where the
transfer resistance of the location is near zero must be assumed.

10
The resistance of the human body depends on the current path and the contact
resistance of the skin. Measurements have shown e.g. approximately 1,000 Ω
for the  ow of current from hand to hand or from hand to foot. Under these
assumptions, a touch voltage of 230 V results in a dangerous shock current of
230 mA. Figure 2 shows the current intensity/exposure time curves in relation to
the physiological reactions of the human body. Dangerous current intensities and
exposure times are those which reach as far as zone 4, as they can cause death
due to ventricular  brillation. It also shows the tripping ranges of the residual
current protective devices with rated residual currents of 10 mA and 30 mA. It
also shows the maximum permissible tripping times according to VDE 0664-10.
As can be seen from the tripping curves, residual current protective devices do
not limit the intensity of the residual current but provide protection due to fast
disconnection of the power and therefore a minimal time of exposure to the
current.
Protection through residual current protective devices
Figure 2: Effects of 50/60 Hz alternating current on the human body
Protection against direct contact (additional protection) with IΔn≤30mA
Zone ①: Exposure is normally imperceptible.
Zone ②: There are generally no injurious effects or muscle spasms.
Zone ③: Muscle cramps can occur. There is normally no danger of
ventricular  brillation.
Zone ④: Ventricular  brillations may occur.
IM
10 mA 30 mA
ms
mA
t
10.000
1.000
100
100
0,1 110 100 1.000 10.000