2
Guide to Selecting a Connector
In selecting a connector, it first must be
determined if a non-environmental (97
A/B Series) type or an environmental
(97E) type is required.
Then the following 8 steps apply to
formulation of a part number.*
How many wires are you
going to connect?
What gauge?
These two questions are important,
because they indicate which insert you
need. There are literally hundreds to
choose from.
The insert arrangements for solder
contact connectors are illustrated on
pages 8-13. The inserts most often
used are highlighted on these pages.
Here’s an example of how to choose
an insert arrangement. Say you want to
connect eight 16-ga. wires, - first find
the section of arrangements contain-
ing 8 contacts. Insert number 20-7 is
the one you want because it contains
eight 16-ga. contacts and it is one of
the most often used. The one you
choose might depend on your space or
voltage requirements. The voltage
capacity of each insert is listed under
its diagram.
If you have more than one wire size
to connect, the method is essentially
the same. Actually, the insert configura-
tions for multiple-size wires are a lot
more flexible than they appear. That’s
because you can always solder a
smaller wire to a larger contact. How-
ever, soldering a large wire to a small
contact isn’t recommended because of
size and current requirements.
What if several identical
connectors have different
functions?
Here’s a situation to watch out for. You
have four identical receptacles on a
panel. One carries high current loads.
The others have low current functions.
A plug mated with the wrong receptacle
(cross-mating) could ruin your valuable
equipment.
To avoid cross-mating, you can
order identical inserts positioned in
both the plugs and receptacles at vari-
ous angles from standard. These varia-
tions from standard position are called
alternate insert positions, and are
described on page 14.
What kind of receptacle do
you need?
For Wall Mounting Use a wall recep-
tacle, type 3100. The elongated back of
this receptacle extends through thick
wall material. It is threaded to accept
standard hardware fittings.
For Unmounted Applications Use
the cable receptacle, type 3101.
For Box or Panel Mounting Use the
box receptacle, type 3102. This recep-
tacle’s back is short to conserve space.
It is not threaded on the back end and
is used when no accessories such as
clamps are needed.
What kind of plug do you
need?
For ordinary situations The straight
plug, type 3106 meets most connector
requirements. However . . .
when space is critical you may want
to consider using an angle plug, type
3108. This type plug lets the cable
enter your equipment at a right angle.
Do you need a plug with a
Solid or Split back shell?
You can get both straight and angle
plugs in solid or split back shell
designs. With the solid shell you have
greater strength and you save space.
On the other hand, the split shell
design lets you quickly inspect the sol-
der terminals when you need to. This
feature could be important if you’ll be
subjecting the connector to rough han-
dling and heavy use.
The designation to use for solid
shell construction in an non-environ-
mental type is the letter A. For a solid
shell construction in the 97E environ-
mental sealing type the designation is
E. This designation letter goes immedi-
ately after the main shell type number:
for example, 3106A or 3108A.
The designation for split shell construc-
tion is the letter B; for example, 3106B
or 3108B. Split shell construction is
available in non-environmental types
only.
Because of application, receptacles
are made in solid backshell construc-
tion only. Their designation is 3100A/E,
3101A/E. (See how to order for solder
contact connectors, page 21, and how
to order for 97E on page 4).
Which connector gets the
socket? - the receptacle or
the plug?
You’re at the point where you designate
which inserts are used with which
shells. Either pin or socket inserts can
be used with plugs or receptacles.
Here’s a good rule of thumb. Order
the sockets for the connector at the
“hot” side of the circuit. By having sock-
ets at the power source, there’s little
chance that a wayward finger or screw-
driver will short the circuit or cause per-
sonal injury.
The designation for sockets is sim-
ply S in a part number, following the
insert code number. For pins, the des-
ignation is P. Therefore, the 20-7P
insert would have pin contacts, while
the 20-7S insert would have socket
contacts.
What type of plating is pre-
ferred?
If you prefer the standard olive cad-
mium, non-reflective, electrically con-
ductive finish, then no suffix number is
required. Other plating variations are
available, including environmentally
friendly zinc alloy. See how to order
instructions for the various plating fin-
ishes offered for 97 Series solder con-
nectors on page 21, and for 97E types
on page 4.
Do you need any
accessories?
Accessories - cable clamps, protection
caps and chains, conduit adapters, and
panel gaskets are shown on pages 35-
41.
* These steps are for solder type connectors which are described in
detail on pages 5-21. If a crimp type connector is needed, the same
steps apply, however, you should consult pages 22-31 for details on
97 Series connectors with crimp contacts. And, for 97E environmen-
tal type connectors, you should consult pages 3 and 4.
1
2
3
4
5
6
7
8