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Alpha
Wire Company Frequently Asked Questions
-
Is the voltage
rating in the catalog specified as Alternating
Current (A.C.) or Direct
Current (D.C.)?
Voltage
rating is expressed in the catalog as Alternating
Current rather than Direct
Current.
- What products
are UL rated or UL approved?
None. Products are either UL Listed (denoted by UL in a circle or parentheses)
or UL Recognized (denoted by a backwards RU symbol). "UL Rated" or "UL
Approved" are incorrect terms that are mistakenly associated with a
product's UL status.
- How do I determine
Bend
Radius for Alpha Wire cables?
When not specified, the following are guidelines for calculating minimum
Bend
Radius:
1. Unshielded Cable -- 10 x Jacket
Diameter
2. Single Shield
-- 12 x Jacket
Diameter
3. Multiple Shield
s -- 15 x Jacket
Diameter
4. Alpha Loc® -- 20 x Jacket
Diameter
- If the Insulation
on cable is rated for 125°C and the jacket is rated for 75°C,
what is the Temperature
Rating of the overall cable?
The overall Temperature
Rating for the cable is 75°C. Overall cable Temperature
Rating is determined by the lowest rating of either the Insulation
or jacket.
- Does UL Recognized
and CSA Certified FIT® tubing require surface printing?
No. UL and CSA have eliminated the surface printing requirement for
both heat shrinkable and non-heat shrinkable tubing. All mandatory information
for both UL Recognized and CSA Certified tubing will appear exclusively
on the product packaging.
- Can Type CM
or PLTC cables be substituted for CL2
or CL3 cables?
Yes. In accordance with the cable substitution hierarchy specifed under
Article 725 of the 1999 National Electrical Code, Type CM or Type PLTC
cables can be substituted for either CL2
or CL3.
- What are the
wiring differences between CEE and North American Color Coding for Cord
Sets?
| STANDARD |
Ground |
LIVE |
NEUTRAL |
| CEE |
Green/Yellow |
Brown |
Light
Blue |
North
American |
Green
Or
Green/Yellow |
Black |
White |
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- What equipment
can be used for printing Alpha Wire FIT®-PRINT markers?
The following printers can be used for Alpha FIT-PRINT:
Standard dot matrix or thermal transfer printers can be used for printing
Alpha FIT®-Print markers.
- Why is clear
FIT®-221 neither UL Recognized Nor CSA Certified?
Both regulatory agency standards UL 224 and CSA 198 specify a requirement
known as the "All Tubing Flame Test". FIT®-221
clear is not flame retardant, and therefore will not pass these minimum
flame test requirements.
- Do I check dimensions
of FIT® Heat Shrinkable Tubing in the supplied or recovered
form?
Both the wall thickness and inner diameter of FIT®
Hheat Shrinkable Tubing are checked in the recovered form only. Wall
thickness and inner diameter dimensions are not specifed in the supplied
form.
- What does the
term "minimum supplied diameter" mean?
This refers to the inside diameter, or I.D., of the tubing as supplied
by the manufacturer. Typically it reflects a minimum value so that the
tubing will readily slide over the object to be covered.
In the case
of tubing that is supplied as a ½-inch, minimum supplied I.D.
and a 2:1 recovery (this means it shrinks to about one-half of its supplied
size), the supplied tubing is always supplied with a minimum I.D. of
0.500-inches.
- What does the
term "maximum recovered I.D." mean?
This refers
to the final inner diameter of the tubing after the tubing has been
fully shrunk, or recovered, through the careful application of heat.
A maximum value is specified to ensure that the tubing will fit snuggly
about the object being covered.
In the case
of a tubing that is supplied as ½-inch minimum supplied I.D.
tubing, with a 2:1 shrink ration, the recovered I.D. will always be
0.250-inches. While this tubing may "recover" to fit a 0.240-inch
item snuggly, it will always recover to provide a snug fit to an object
0.250-inches.
- What happens
to the tubing wall thickness when the tubing is recovered?
After
recovery, the tubing wall thickness increase to some extent. Because
of some variability, the recovered wall thickness is generally specified
as a nominal value.
- What size FIT®
Heat Shrinkable Tubing should I use for my application?
The basic
answer is that it depends upon the specific application.
A practical
approach to determining the size of tubing to use is simply to use one
that will shrink to about 70% of the minimum supplied I.D. For example,
to cover a cylinder of diameter ¾-inch, a tubing with a minimum
supplied diameter of 1-inch should be used. To cover a ½-inch
bar, a ¾-inch tube should be used. Now, for this latter case
a 2:1 shrink ratio tubing could be used if one wished to maximize the
recovered wall thickness.
- How do I know
what is the best FIT® Heat Shrinkable Tubing material
to select for my application?
First,
think about how you wish to use FIT® Heat Shrinkable
Tubing . . . is it for:
- Bonding
- Breakouts
- Bundling
- Color coding
- Encapsulation
- Environmental
protection - direct burial
- Environmental
protection - immersion
- Environmental
protection - splashing
- Fixturing
- Holding
- Identification
- Mechanical protection
- Special properties
(fire protection, conductivity, LSOH applications)
- Strain relief
The Alpha
Wire Master Catalog provides information as to what materials are
best suited for these types, as well as other, applications.
Next, determine
if your operating environment is varied, i.e.,
- Hot and cold
temperatures
- Assorted chemical
exposure
- Combined mechanical
abuse . . . abrasion and flexing, vibration and impact, etc.
- Fire situations
- Ultraviolet and
ozone exposure
- EMI and RFI exposure
Again, the Alpha
Wire Master Catalog provides an extensive list of properties for
the different tubing types and materials.
Once the application
and environmental conditions are understood, then the proper tubing
material may be selected.
- What is the
best way to recover FIT® Heat Shrinkable Tubing?
This is very important
since many people appear to get into "trouble" when they
attempt to recover heat shrinkable tubing.
There are several
methods to recover heat shrinkable tubing, from an open flame, low
velocity torch, or high heat light sources to precision hot air sources
to the most common, the standard heat gun.
If done properly,
any of these sources will result in good tubing recovery; done improperly,
each will provide poor recovery at best and tubing/substrate damage
at worst. We will review the recovery technique through a review of
two typical examples.
Example A:
Assume that we
must make a repair to the black PVC covering on a 3-ft. metal tube
with an OD of about 1-inch. The breach in the tube's PVC cover in
at the midsection of the tube and is about 4-inches in length. First
let's assemble the tools required . . .
- Since we wish
to repair the breach with a similar material we will select an Alpha
Wire FIT®-105, black, PVC based, FIT® Heat Shrinkable Tubing.
- Since the tube
OD is about 1-inch and this tubing has a 2:1 shrink ratio (it recovers
to 50% of it's original, supplied size) we may use an Alpha Wire
FIT®-105-2, or a 2-inch, supplied ID product. If we would like
a somewhat tighter fit, we would recommend an Alpha Wire FIT®-105-1-1/2
that will recover to a ¾-inch diameter.
- Since the breach
is about 4-inches and we wish to overlap the area plus account for
some longitudinal shrinkage, we will require about 6-7-inches of
the Alpha Wire FIT®-105 Heat Shrinkable Tubing.
- The Alpha Wire
FIT®-105 Heat Shrinkable Tubing recovers at a low temperature,
about 100°C so an Alpha Wire FIT® Gun-3 will suffice (temperature:
400°C - 585°C). The performance of this gun is more than
adequate for the job.
Now to the actual
restoration (or repair) . . .
- Carefully trim
away any loose sections of the original covering so that a neat section
of exposed tubing is visually apparent and the remaining covering
is close fitting to the tube.
- Slide the length
of repair Alpha Wire FIT®-105 over the breach, centering over
the breach (the tubing should cover the entire void plus provide overlap
to each end of the remaining tube covering.
- With the heat
gun at temperature carefully heat the tubing at the MIDSECTION keeping
the heat gun constantly moving about the tube perimeter. If you stop,
or dwell too long, you will DAMAGE the tubing. As the tubing begins
to recover, continue to heat about the perimeter, working your way
towards the tubing end. Once complete (recovered), begin to recover
the remaining half of the restoration tubing, starting at the center,
traversing about the perimeter and out towards the restoration tubing
edge.
- Once complete,
the restoration tubing will fit tightly about the tubing (you may
see a ridge where the underlying covering and tubing meet) and there
will be neither gaps nor burnt sections.
Example B:
Assume that we must
protect a section of bare copper wire that passes through a very caustic
environment. The wire section to be protected is 18-inches in length
and each end of the wire exits outside the area of caustic chemical.
The wire to be protected is a 10 AWG.
First let's assemble
the tools required . . .
- Since we have
a very harsh environment, we choose to protect the wire with a FIT®
Heat Shrinkable Tubing made of TFE Teflon™, a material resistant
to almost every known chemical at room temperature.
- Since the wire
to be protected is a #10 AWG, we may use an Alpha Wire FIT®-500-10
with a shrink ration of about 1.5:1. Since we are required to protect
a wire some 18-inches in length, we will use a standard 24-inch length
of Alpha Wire FIT®-500 product. We will use the entire 24-inch
length since we don't know the specifics of how the tube passes through
the vessel wall that house the caustic chemical.
- The Alpha Wire
FIT®-105 Heat Shrinkable Tubing recovers at a low temperature,
about 100°C so an Alpha Wire FIT® Gun-3 will suffice (temperature:
400°C - 585°C). The performance of this gun is more than adequate
for the job!
Now to the actual
restoration (or repair) . . .
- Place the length
of Alpha Wire FIT®-500 over the wire.
- Since the wire
to be covered is relatively small, the reflector will be fitted to
the heat gun (this reflector allows the entire perimeter of the wire
and tubing to be heated without need to keep the gun in motion about
the wire perimeter.)
- With the heat
gun at temperature carefully heat the tubing and wire at the MIDSECTION
keeping the heat gun moving from the center to one end of the applied
Alpha Wire FIT®-500 Heat Shrinkable Tubing. Once recovered, start
at the center section again, and recover the remaining half of the
tubing moving towards the other end of the wire and tubing.
- In this case,
if you stop, or dwell too long, you will not damage either the tubing
or the wire since both are very resilient to heat.
There you have it,
two examples of FIT® Heat Shrinkable Tubing recovery without damage.
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