Summary presentation from a white paper delivered to PCIC Middle East February 2014, introducing engineering design methods for cable transit devices (MCT's), best practices for use of these solutions and engineering work process.

1. Multi Cable Transit Devices:
Applications and Design Methods
Allen Gibson, Roxtec Group
Bo Millevik, Roxtec Group
Alan Bozek, EngWorks, Inc.

2. PCIC MIDDLE-EAST 20142
Summary
• Introduction - Background
• Critical components, configurations and proper sizing of cable transits
• Protection, ratings & benefits
• Applications
• Comparing field-based decisions to proven engineering methods
• Checkpoints - Specifications for cable entries
• Checkpoints – QA / QC for MCT installations
• Conclusion

3. PCIC MIDDLE-EAST 20143
Introduction
• Multi cable transit (MCT) devices
commercialized since 1950’s
• Original designs to prevent water and
fire passage within submarines and
marine vessels
• MCT devices accepted as standard
design and safety practice through
most marine and offshore oil/gas
applications
− DNV, ABS, USCG, Lloyds, etc.
• Today = Transferring the knowledge
from marine/offshore to land-based
industrial applications
3.7.5
cable transit device
an entry device, intended for one or
more cables, with a seal made up
of one or more
separate elastomeric modules or
parts of modules (modular internal
seal), which are
compressed together when the
device is assembled and mounted
as intended.
NOTE Cable transit devices can also serve as
Ex blanking Elements when the elastomeric
modules provided allow for this function.

4. PCIC MIDDLE-EAST 20144
Multi Cable Transits – Simply Stated
• Best value when used for
high cable density when
more than one demand is
present
− Fire+IP
− Blast +rodent
− Vapor tight + blast
− Etc.
• When maintenance,
expansion or future
access for cables or pipes
will be required

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MCT Devices – Critical Components
• Frame (window)
• Modules (inserts)
− Fixed diameter
− Adaptable layers with core
− Insert blocks
• Stay plates (dividers)
• Compression (wedge or unit)

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Applications – Walls & Floors

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Applications – Terminal / Junction Boxes

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Applications – Pre Terminated Connectors

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MCT Devices – Configurations
• Flanged
• Non-flanged
• Multiple windows – vertical
• Multiple windows – horizontal
• Combination
• Proper framing of aperture is critical

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MCT Devices – Sizing / Packing Space
• Early engineering decisions =
project savings
• Get the aperture size correct…
FIRST
• Consider spare capacity for future
expansions and upgrades
• Communicate aperture size
requirements to civil design and
building contractors…BEFORE
construction begins

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Protection: Environmental (IP)
• Most standard MCT
designs should have a
minimum water tight and
dust tight rating
equivalent to an Ingress
Protection (IP) rating for
electrical enclosures of
IP 54 as defined by IEC
60529.
• Wall / floor applications
for MCT’s should be
defined by the
environmental
performance
requirements of the
structure

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Protection: Blast
• Blast rating EX,
ATEX or HazLoc
approval
• Cable entries must be
considered in design of
blast-rated structures,
just as doors and
windows
• MCT devices are
commonly available to
provide protection
against blast load to >10
psi for > 60 milliseconds.

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Protection: Vapor-tight barrier
• Definition – “a barrier that
will not allow the passage
of significant quantities of
gas or vapor at
atmospheric pressure”
API RP 500/505
• Effective way of locating
non-hazardous rated
equipment adjacent
hazardous areas

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Protection: Vapor-tight barrier
An unclassified room or
building may be installed
adjacent to a classified
area provided a vapor-tight
barrier is placed between
the hazardous location and
the unclassified area.
•Benefits
− Reduce on-site wiring costs
− Allows equipment to be pre-
commissioned

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Protection: Hazardous locations
• Cable transit devices are
recognized and approved
for use according to IEC
60079-0
• MCT devices used in
electrical equipment
within hazardous
locations MUST be
properly certified and
labeled
3.7.5
cable transit device
an entry device, intended for one or more
cables, with a seal made up of one or more
separate elastomeric modules or parts of
modules (modular internal seal), which are
compressed together when the device is
assembled and mounted as intended.
NOTE Cable transit devices can also serve as Ex
blanking Elements when the elastomeric modules
provided allow for this function.

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Protection: Earthing, bonding & EMC
«EMC, ElectroMagnetic Compatibility »
•Cable segregation
•Single Entry Panel

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Protection: Earthing, bonding & EMC
« Metallic layers inside cables should be connected to earth »
•Electrical safety
− Protective Earthing
− Equipotential Bonding
•Lightning Protection
•Electro Magnetic Interference (EMI)

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Protection: Earthing, bonding & EMC

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Protection: Fire Barrier
• MCT’s can provide 30
minute to 4 hour
protection as a passive
fire barrier
• Jet fire, A60, H60,
UL1479 and more
• Some fire rated
installations require
installation of mineral
wool insulation to comply
with certifications

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Protection: Fire Barrier

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Protection: Rodents, Pests, Snakes…
“Have you experienced accidents,
downtime or damage from mice, rats,
insects, snakes, etc. in your motor control,
switch gear or other electrical cabinets?”

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Protection: Rodents, Insects & Snakes
“I've spent quite a few
years fixing
communications equipment
contaminated by ants or
dead lizards.
Some years ago I had to fix
some Optical Fibre
equipment where mice had
bitten through the fibre to
either the transmitter or the
receiver; as well as fouling
the PCB assembly.”
Electrical Project Engineer

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Protection: Rodents, Insects & Snakes
“I'm involved in a project
where the 15 kV service-
entrance gear to a facility is
mouse and rat-infested.
They've chewed the
insulation on conductors,
and generally left trails all
over everything….I'd really
like to see the building
sealed tight.”
John M
http://forums.mikeholt.com/showthread.php?
t=144240

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Protection: Rodents, Insects & Snakes
“Yes. I experienced rodent
entry into HV and MV
switch gear in different
companies I worked with.
Twice lizard entered into
MV switch gear, caused
flash over which led to total
power failure. Once a
snake entered into 11KV
switchgear and resulted in
trip of the bus section…”

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Protection: Rodents, Insects & Snakes
…In both cases the
identified reasons were
similar. Openings in
switch gear providing
access to cable
compartment, growth of
grass and weeds around
the substation and non
installation of rodent
repeller in the substation.
The total power failure was
due to failure of protection
system and problems with
protection coordination.”
Senior Electrical Engineer

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Work Process & Design Approach
Critical Decision: Field decision or engineering decision?
OR

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Work Process & Design Approach
Critical Decision: Field decision or engineering decision?

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Work Process & Design Approach
Critical Decision: Field decision or engineering decision?

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Work Process & Design Approach
Critical Decision: Field decision or engineering decision?

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Project
Award
FEED
Decision for
cable entry
methods,
EMC
requirements
& project
standards
Detailed
Engineering
Constructio
nEPC Installation Completion
Preliminary
MCT
drawings to
develop
apertures /
cut-out sizing.
Approved
Vendor List
Engineering
specification
–
Frame
configuration
and
acceptance
Bill of
Material
finalized from
final cable
schedules
Materials list
to relevant
sub-suppliers
Confirm frame specs
Detail design of
modules
Logistical services
On-site installation
training to contractors
& maintenance teams
On site
validation
inspections
Project
documentatio
n
Work Process & Design Approach

31. PCIC MIDDLE-EAST 201431
EPC / Design – Required Information Input
MCT
Design
Software
Issue Cable
Transit
Schedule
NO: return to MCT
manufacturer with Comments
Cable
Schedule
Equipment
Layouts
Building
Layouts
Cable
Routing
Cable
Specification
Installation
Specifcation
Cable type &
description
Cable #,
routing to/From
Location of
Transit
Installation
Requirements
Info
Share
to
Vendor
Cable data to
MCT Vendor for
Design
Client Input Data to
Transit Designer
Transit Detail
Drawings
Bill of Material
Certifications &
Installation
Instructions
Issue specification
Check
and
Approved
Yes
No
MCT Manufacturer – Required Actions and Output
OR
Work Process – MCT Design

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Specification Checkpoints for Multi Cable Transits
Variables
•Blast load demands
•Fire demands
•Environmental (weather) or IP
demands
•Operating Temperature
•Cable retention or pull force
demands
•Corrosion demands / material
requirements
•Preferred installation method
•Bonding, earthing, EMC demands
Interfaces
•Application - wall / floor / enclosure
•Structure Material
•Cable

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Simple QA / QC checkpoints for MCT installations:
• Fully-tightened compression unit – most common failure point!
• Flashlight / daylight test – if you can see light through the transit, it
should be re-installed or compression tightened
• Pull test – a simple pull on the cables will confirm proper installation
− Slippage indicates oversized insert block for cable O.D., or
− Lack of proper compression
Installation Checkpoints for Multi Cable Transits

34. PCIC MIDDLE-EAST 201434
Conclusions
• Project owners / end users should develop, then communicate
standards for cable entries
− This will increase project safety, improve project efficiencies, and reduce
design and installation risks –
− we should learn from offshore & marine markets
• MCT devices are simple, fit-for-purpose solutions that can add
protection to your projects, people, equipment and operations against
the hazards of blast, fire, weather (IP), rodents and vapors
• MCT devices are available for retro-fit to exsisting openings without
removal / re-glanding of cables
• Manufacturers are readily available to provide MCT design support as
well as onsite trainings and inspections and should be consulted early
in projects to optimize efficiency and safety