The circuit schedule shows all of the information that is needed
to pull and terminate each circuit.
Terminations and Circuit Schedules
Example of a circuit schedule
The schematic (or diagram) is a graphical
representation of how cables are terminated
in a terminal block.
For example - look at this circuit number
This is a more detailed description of
where the circuit is routed from.
If there are further comments they would be listed here. Here they are more detailed
descriptions of what the cables are going to.
This is a more detailed description of where the circuit is routed to.
This shows which schematic the cable is routed from. In this case EI-703 represents the engineer's drawing number and the 110-ER-0003-001 SH72 is the vendor's drawing schematic number.
This shows which schematic the cable is routed from. In this case EI-701 represents the engineer's drawing number and the 110-ER-0003-001 SH72 is the vendor's drawing number.
This shows the cable type that is to be
pulled. Here the "V" stands for vendor,
KX is a thermocouple type cable and 1P16 is 1 twisted pair 16 gauge cable.
This column shows
the equipment number
that the circuit is written from.
These are circuit numbers. Each number represents a cable that needs to be pulled
This column shows
the equipment number
that the circuit is written to.
If the circuit
goes to a specific
section of a
junction box
its listed here.
TBB means
"Terminal Block - B"
The engineer typically proves the routing
which would show which conduits the cables are supposed to go through. These are vendor supplied cables and vendor routed cables so there isn't a specific route. The engineer typically includes a length as well.
Terminated on TBB - Terminal block "B"
This is the same circuit name on the schematic
Location of conductors are landed
This is the type of cable
(yellow)
This is the device it's
terminated to
Drawing number
Here the screw is tightened
against the conductor. If the
specifications had required
ferrules they would have been
used here.
A good termination won't show
any conductor under the terminal.
Termination diagram for an instrument
Ring Term
Insulated
fork
Below are some common types of terminations.
Check specifications to see what is required.
Ferrule
Ferrules are sometimes required in the
specifications. They are used to make sure that all of the conductors make good contact with the terminal. Ferrules are generally an extra step that we try to avoid if possible.
Uninsulated
fork
Fork
These are typically preferred over ring
terms because you don't have to completely
remove the screw to set the wire in.
We try to avoid these for the same
reason that we prefer fork. Also,
if startup has to go through and
remove any wires, they then have
to take the screw completely out.
Ring
One of our best practices is to
use a cable stripper instead of a knife
to cut the jacket off.
Once the jacket is off a regular
pair of strippers can be used to
strip the insulation to get to the
bare conductor.
Crimping tools are made of specific types of lugs and brands. Make sure the correct tools are purchased.
Motor terminated with lugs
on a terminal block.
Long barrel one hole
Cable in a panel terminated
directly onto a block without a lug
Types of lugs
Long barrel two hole
Cable terminated on bus
with lugs
Short barrel one hole
Tools for crimping lugs
Again, a wire stripper is
used to expose the
conductor
Battery operated
Hydraulically operated
Mechanically operated
Range of lugs
Dies go inside of the tools
to make sure the connection is correct
- Small instrument and control cable
- Power cables - lug terminations
- Power cables - motors
- Power cables - wire nuts
- Medium Voltage
Some motors come
with terminal blocks
In other motors the leads
are lose and need to be
spliced to the feeder.
Lead Kit
This can be done by either
taping them together or a
motor lead connection kit
can be bought.
Taped
Typically we only use wire nuts
on non process work - lighting and
receptacles.
Wire nuts are rated for different sizes by color. The correct nut must be used.
Weather tight spring nuts must be used outdoors
With a load break elbow,
the connection is actually
inside of the insulated boot
An example of how a medium voltage termination is made
Another best practice is to
use the speed systems product
on medium voltage terminations.
This one tool will strip the jacket,
the semiconductor and the insulation without the need for a knife.
A live front termination
is connected straight to
the buss with no additional
protection
Cold shrink is easier and safer than using heat shrink.