Installation 
28  UDC3500 Universal Digital Controller Product Manual  3/07 
 
Earth
Ground
Hot
Neutral
AC/DC 
Line  
Voltage
1
2
PROTECTIVE BONDING (grounding) of this controller and the enclosure in which it is 
installed, shall be in accordance with National and local electrical codes. To minimize 
electrical noise and transients that may adversely affect the system, supplementary 
bonding of the controller enclosure to local ground using a No. 12 (4 mm
2
) copper 
conductor is recommended. Before powering the controller, see “Prelimnary Checks” in 
this section of the Product Manual.
1
It is the user’s responsibility to provide a switch and non-time delay (North America), 
quick-acting, high breaking capacity, Type F (Europe), 1/2A, 250V fuse(s), or circuit -
breaker for 90-264 Vac applications; or 2 A, 125 V fuse or circuit breaker for 2 4 Vac/dc 
applications, as part of the installation.
Applying 90-264 Vac to an instrument rated for 24 Vac/dc will severely 
damage the instrument and is a fire and smoke hazard.
3
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
L1
L2/N
22
23
24
25
26
27
18
19
20
21
31
32
33
34
35
36
28
29
30
Earth
Ground
Hot
Neutral
AC/DC 
Line  
Voltage
1
2
PROTECTIVE BONDING (grounding) of this controller and the enclosure in which it is 
installed, shall be in accordance with National and local electrical codes. To minimize 
electrical noise and transients that may adversely affect the system, supplementary 
bonding of the controller enclosure to local ground using a No. 12 (4 mm
2
) copper 
conductor is recommended. Before powering the controller, see “Prelimnary Checks” in 
this section of the Product Manual.
1
It is the user’s responsibility to provide a switch and non-time delay (North America), 
quick-acting, high breaking capacity, Type F (Europe), 1/2A, 250V fuse(s), or circuit -
breaker for 90-264 Vac applications; or 2 A, 125 V fuse or circuit breaker for 2 4 Vac/dc 
applications, as part of the installation.
Applying 90-264 Vac to an instrument rated for 24 Vac/dc will severely 
damage the instrument and is a fire and smoke hazard.
3
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
L1
L2/N
22
23
24
25
26
27
18
19
20
21
31
32
33
34
35
36
28
29
30
 
Figure 2-5 Mains Power Supply