Datasheet

90°
For further information and full technical data, visit phoenixcontact.net/products
605 PHOENIX CONTACT
The screw terminal blocks in the UT ...
and UKH ... series are suitable for the direct
connection of aluminum conductors
according to the directives governing
conductor pretreatment.
The aluminum
“yields”, i.e., under pressure, aluminum
yields more strongly than copper due to a
low modulus of elasticity. Furthermore,
after stripping the aluminum conductor, an
oxide layer forms on the conductor surface
due to reacting with air. This oxide layer
leads to increased contact resistance
between the aluminum conductor and the
terminal point. The oxide layer should
therefore be removed before wiring. In
addition, the maximum current carrying
capacity of aluminum conductors is lower
Approved combinations of screw connection terminal blocks with aluminum conductors
Color versions of terminal block series are included in the approval.
Terminal block
Conductor cross section [mm
2
]
Recommended tightening torque
2.5 4 6 10 16 25 35 50 70 95 120 150 185 250
UT 2,5 (-PE) RE RE
0.6 Nm
UT 4 (-PE) RE RE RE
0.8 Nm
UT 6 (-PE) RE RE RE RE
1.8 Nm
UT 10 (-PE) RE RE RE RE RE
1.8 Nm
UT 16 (-PE) RE RE RE RE RE RE
3.0 Nm
UT 35 (-PE) RE RE RE RE RE RE RE
3.7 Nm
UKH 25 RE RE RE RE
4.5 Nm
UKH 50 RE SE
8 Nm
UKH 70 SE SE
10 Nm
UKH 95 SE SE
20 Nm
UKH 150 SE SE
30 Nm
UKH 240 SE SE
30 Nm
RE Round, single-strand, class 1; approved
SE Sector-shaped, single-strand, class 1 α = 90°; approved
Connecting aluminum conductors
than that of copper conductors. In general,
if the same current carrying capacity is
required of the aluminum conductor, a
larger cross section than for a copper
conductor must be selected. Based on the
properties specified, UT ... and UKH ...
screw connection terminal blocks from
Phoenix Contact have been qualified
through extensive tests for the use of
aluminum conductors. An important quality
feature of this qualification is the 1000-hour
current cycling test according to IEC 61545.
As part of this test, the terminal block and
aluminum conductor combination is
supplied with current for an hour and then
switched off for an hour. The cycle is
repeated 500 times. During the 1000 hours,
temperature measurements are taken at the
terminal points according to a defined
schedule. The measured values must not
exceed defined limit values. All screw
connection terminal blocks from Phoenix
Contact that have undergone these tests
are listed in the table below.
Single-strand aluminum conductors in
round (RE) form up to 35 mm
2
with the
relevant approved cross section can be
connected directly to the above-listed feed-
through terminal blocks with screw
connection. When connecting aluminum
conductors that are 50 mm
2
and above, only
sector-shaped, single-strand conductors
(SE) may be used and they must be inserted
as illustrated.
When directly connecting aluminum
conductors to UT ... and UKH ... feed-
through terminal blocks from Phoenix
Contact, the following guidelines on
conductor pretreatment must be followed:
- The oxide layer must be removed from the
stripped end of the aluminum conductor
using a blade (suitable knife,
e.g.,
WIREFOX-D 13 stripping tool)
.
- It must immediately then be dipped in non-
acid and non-alkali, i.e., neutral, Vaseline.
- The installation location must be kept free
from humidity or aggressive atmospheres.
- When using an aluminum conductor, the
screw in the clamping part of the screw
terminal block must be tightened with the
recommended tightening torque of the
respective terminal block; there is no need
to tighten the terminal point. (For torque
screwdrivers, see Catalog 5)
- The pretreatment must be repeated when
connecting the conductors anew.
Sector-shaped aluminum conductors
should be inserted in the terminal point of
UKH ... terminal blocks as illustrated. The
rounded section of the conductor should be
at the top so that the right-angled area of
the aluminum conductor is positioned on
the prism-shaped base of the terminal
sleeve.
Accessories, e.g., bi-metal cable lugs
(Al/Cu pressure cable lugs) can be used to
connect stranded aluminum conductors.
See phoenixcontact.net/products
Example for UKH ... – connecting sector-shaped, single-strand
aluminum conductors
Technical information
Connection of aluminum conductors