Multiple Disconnect Safety
System
Installation and Operating
Instructions
Important Safety Instructions
Save These Instructions
© 2011-2012, 2014 Bentek, Inc. All rights reserved.
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including indirect, incidental, or consequential damages, caused by reliance on the material
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forth in written agreements between Bentek and its customers. No representation or other
affirmation of fact contained in this publication shall be deemed to be a warranty or give rise to
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limited to, the implied warranties of merchantability and fitness for a particular purpose.
Bentek Corp.
2350 Harris Way
San Jose, CA 95131
1-866-505-0303
1-408-954-9600
1-888-202-5009 (Support)
www.benteksolar.com
Multiple Disconnect Safety System Installation and Operating Instructions
Part 950-001568-000 Rev A
March 2014
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 3
Table of Contents
About This Book 5
Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Notation Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Manual Organization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Document Revisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Chapter 1: Safety Instructions 7
Information for Technicians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 2: Product Description 9
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Explanation of Symbols Used on Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Chapter 3: Installation Procedure 17
Required Tools and Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Preparing to Install the MDSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Opening and Closing the Enclosure Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Opening the Dead Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Mounting the MDSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Preparing the Cutouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Connecting Wires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Connecting Conductors from Source Circuits . . . . . . . . . . . . . . . . . . . . . . . . . 34
Attaching Conductors From The Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Finalizing the Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Preventative Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 4
Contents
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 5
About This Book
This manual provides information on installing the Bentek Multiple Disconnect
Safety System. Information is included on mounting the equipment on a
prepared base and connecting the wires to the proper locations.
Intended Audience
This manual is for those qualified to deal with the dangers and hazards involved
in installing electric devices. Those using this manual should be skilled in reading
site plans and electrical wiring schematics. Users should be familiar with meeting
requirements contained in UL 50, “Standard for Enclosures for Electrical
Equipment,” UL 514B, “Standard for Safety Conduit, Tubing and Cable Fittings,”
National Electrical Code, ANSI/NFPA 70, and other applicable standards
documents.
Notation Conventions
This manual uses the following notation conventions:
WARNING
Warns you of something that could result in physical injury or death.
CAUTIONCAUTION
Cautions you against anything that may damage equipment.
NOTE
Provides information of special interest or importance.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 6
About This Book
Manual Organization
This manual is organized as follows:
Chapter 1, “Safety Instructions,” provides information on warnings and
guidelines for installing the product safely.
Chapter 2, “Product Description,” describes the MDSS and provides
specifications.
Chapter 3, “Installation Procedure,” describes how to install the MDSS.
Document Revisions
Revision ECO# Description Date Author Approval
Z1 Initial release. 9/8/11 GLB DAC
Z2 Update torque values. 9/26/11 GLB DAC
Z3 Two-sided printing; dead
front model change;
remove torque.
3/15/12 GLB MS
A Correct drawings for
bottom panel for
single-column MDSS.
3/25/14 GLB JW
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 7
Chapter 1
Safety Instructions
This manual contains important safety instructions for the following Bentek
MDSS equipment:
NOTE
In model numbers, xx refers to the number of switches and yyy refers to the
switch rating while DF refers to Dead Front.
You must follow these instructions during maintenance of the inverter or
combiner box. Save these instructions.
WARNING
The installation, adjustment, or repair of Bentek MDSS equipment involves risk
of contact with potentially lethal voltages and currents. These servicing
instructions are for use by qualified personnel only. To reduce the risk of electric
shock, do not perform any servicing other than that specified in the operating
instructions unless you are qualified to do so.
There are no user-serviceable parts inside the MDSS equipment. Refer servicing
to qualified personnel.
The enclosure door should remain closed while the MDSS is operational.
Servicing or adjustments should not be performed while the circuits are
energized.
You must follow the instructions in this manual during maintenance of the
inverter or combiner box. Save these instructions.
CAUTIONCAUTION
Ensure the unit is properly secured at all times. It may be a tipping hazard in the
shipping container as well as after packaging is removed. Mounting the unit on
the prepared base eliminates the tipping hazard.
Model # BTK6-MDSS-xxyyy Model # BTK6-MDSS-xxyyy-DF
Model # BTK10-MDSS-xxyyy Model # BTK10-MDSS-xxyyy-DF
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 8
Chapter 1: Safety Instructions
WARNING
Inputs from the field panel and outputs to the inverter may be hot! Do not touch
components or parts associated with these connection points. Severe burns or
death can occur.
Install the MDSS enclosure so that it conforms to national and local safety
and operational codes (NEC and CSA).
The enclosure must only be opened and serviced by authorized and
knowledgeable service and/or contract personnel.
Read this manual and understand all safety, installation, and operational
information before opening or working on this device or any of its
connections or components.
If you have questions that are not answered in this document, contact Bentek
Support at 1-888-202-5009 or at www.benteksolar.com.
Information for Technicians
It is your responsibility as the installation technician to follow these instructions
during installation and/or maintenance of Bentek MDSS equipment.
WARNING
Risk of electrical shock exists from energy stored in the inverters. The inverters
contain energy storage devices that require 15 minutes in order to safely
discharge their lethal voltages after disconnecting all sources of supply.
You are advised that:
Upon connection, this unit is under voltage. At this point, the equipment
contains lethal DC voltages.
When the photovoltaic (PV) array is exposed to light, it supplies DC voltage
to this equipment.
As the installer, you must reference the National Electric Code (NEC) sections
250 and 690 to ensure proper system wiring and grounding compliance. In
addition, all state and federal Occupational Safety and Health Administration
(OSHA) guidelines and regulations must be followed.
Unless otherwise specified, wiring methods must be in accordance with the
National Electrical Code, ANSI/NFPA 70.
Installations in Canada shall be in accordance with the Canadian Electrical
Code, Part I.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 9
Chapter 2
Product Description
The Bentek Solar Multiple Disconnect Safety System (MDSS) is designed for
large PV solar systems (250KW or greater) and is intended for installation next to
the inverter. It is comprised of multiple UL 600VDC or 1000VDC load-break
disconnects contained in one easy-to-install compact enclosure. The MDSS
provides an unmatched safe and convenient means of isolating and diagnosing
individual DC portions of a PV system for routine maintenance and
troubleshooting.
Maximum current through each circuit of the MDSS is determined by the
disconnect used.
The MDSS is available in several configurations:
The double-stack MDSS provides up to five double-stacked disconnects, or
ten switches. Each double-stacked disconnect contains an upper disconnect
and a lower disconnect, both controlled by the same disconnect handle. This
model is available in 100A, 200/250A, and 400A configurations.
The dual-column 100A and 200/250A MDSS provides up to ten disconnects
arranged in two columns.
The single-column 100A, 200/250A, and 400A MDSS provides up to eight
disconnects arranged in a single column.
Depending on the number of disconnects needed, a configuration can include
both double-stacked disconnects and single disconnects in the same MDSS
enclosure.
Optionally, the disconnect handles may be installed on a dead front within the
MDSS enclosure instead of on the front door.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 10
Chapter 2: Product Description
Figure 1 MDSS (front views)
With nine dual-column disconnects— With eight single-column disconnects—
handles installed on dead front
handles installed on front door
(handles in off position) (handles in off position)
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 11
Chapter 2: Product Description
Specifications
Tabl e 1 through Table 4 show the specifications for MDSS models.
NOTE
In model numbers, xx refers to the number of switches and yyy refers to the
switch rating while DF refers to Dead Front.
Ta b le 1 Electrical Specifications of MDSS
Model
Max #
of
Strings
Installed
Disconnect
Switch
Rating (A)
Max
Voltage
(VDC) Connection Size
Internal
Operating
Temp
Range
BTK6-MDSS-xxyyy,
BTK6-MDSS-xxyyy-DF
8100
600
300
MCM
M10
bolt
-25o C to
+50o C
8 200/250
8400 600
MCM
BTK10-MDSS-xxyyy,
BTK10-MDSS-xxyyy-DF
10 100
1000
300
MCM
10 200/250
10 400 600
MCM
Ta b le 2 Physical Specifications of MDSS
Height (of enclosure) 79 inches
Additional height due to eyebolt 2.5 inches
Width 32 inches
Depth (excluding handles) 24 inches
Weight, approx. (unwired) 450 pounds
Additional weight of dead front 75 pounds
Ta b le 3 Environmental Specifications of MDSS
Maximum operating altitude 6500 feet
Relative humidity 95%
Ambient temperature range -25o C to +50o C
If temperatures and altitude exceed these specifications, contact your
Bentek representative to determinable suitability.
Ta b le 4 Certifications
ISO 9001:2008 Quality certified.
ETL Listed to UL1741.
ETL Listed to CSA 22.2 No. 107 (600V only).
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 12
Chapter 2: Product Description
Components
The MDSS is a prewired, floor-mounted NEMA-3R electrical enclosure that
contains the following components:
Disconnects—600VDC or 1000VDC interrupt switches.
Plastic Shields or Phase Barriers—Guards that increase safety by preventing
unintentional contact with live parts.
Extended Terminal (optional)—Extension to the input and output terminals.
Ground Busbar—Copper bar with aluminum terminals used to combine
individual source circuit grounds to system ground.
Dead Front (optional)—Disconnect handles are installed on an internal door
or panel inside the enclosure instead of on the front of the enclosure.
NOTE
Bentek assemblies may use components that are silver plated. This plating may
oxidize (tarnish) over time as a result of natural exposure to standard
atmospheric conditions and become brownish, yellow, off-color or mottled in
appearance. This process is normal and should not be mistaken for indications of
over current. The oxidation of the silver plating will not affect the performance of
the assembly in any way.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 13
Chapter 2: Product Description
Figure 2 MDSS with four double-stack 1000V/400A disconnects - inside front view
Double-stack disconnect units, each
containing an upper and a lower unit
Input #1
(upper)
Input #2
(lower)
Output #1
(upper)
Output #2
(lower)
Input #7
(upper)
Input #8
(lower)
Output #7
(upper)
Output #8
(lower)
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 14
Chapter 2: Product Description
Figure 3 MDSS with 10 dual-column 1000V/250A disconnect units - inside front
view
Input #1
Output #1
Input #2
Output #2
Input #9
Output #9
Input #10
Output #10
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 15
Chapter 2: Product Description
Figure 4 MDSS with 8 single-column 600V/100A disconnect units - inside front
view
Input #1
Output #1
Input #8
Output #8
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 16
Chapter 2: Product Description
Explanation of Symbols Used on Equipment
The following symbols are used to identify parts and provide warnings for the
MDSS.
Ta b le 5 Symbols on Equipment
ELECTRICAL SHOCK HAZARD—This symbol indicates the
presence of electric shock hazards. Enclosures marked with
these symbols should only be opened by an authorized
service provider.
WARNING: To avoid risk of injury from electric shock, do not
open this enclosure.
GROUND—This symbol identifies the equipment ground
points.
“ON”—This symbol identifies that the item is in the “on”
position.
“OFF”—This symbol identifies that the item is in the “off”
position.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 17
Chapter 3
Installation Procedure
This chapter describes the mounting and wiring or connections required to
install the MDSS.
Prior to mounting and wiring the MDSS, remove any shipping supports or
materials.
Contact Bentek Support at 1-888-202-5009 for additional assistance.
Required Tools and Materials
Standard construction, electrical tools, and basic electrical safety and testing
instruments are required for the installation of the MDSS enclosure. Additionally,
the installation requires:
Calibrated torque wrench.
Personal protective equipment such as electrical safety gloves, safety
goggles, etc.
Installers must reference the specific site scope and project drawings, including
the system layout and related electrical drawings, for additional information and
considerations.
CAUTIONCAUTION
The installer is responsible for verifying placement of internal assemblies prior to
drilling holes and making any cutouts in the chassis.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 18
Chapter 3: Installation Procedure
Preparing to Install the MDSS
Refer to the project drawings to identify the mounting location and any specific
location requirements or special instructions. The MDSS must be mounted in a
position and at a location where the door is easily accessible.
Figure 5 Diagram of the required door swing
The mounting base must be at least as large as the enclosure to be mounted and
be able to support the weight of the equipment.
NOTES
When floor mounting the enclosure, it must be secured to a supporting
structure to prevent potential movement. The bottom skin may be drilled to
accommodate bolting to the floor.
Due to the option of removing the bottom gland plate, code may require any
exposed bottom substrate to be non-combustible.
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 19
Chapter 3: Installation Procedure
Opening and Closing the Enclosure Door
Up to ten disconnect handles (depending on the model) are located on the front
of the enclosure or on the optional dead front. When the handles are on the
door, each of these handles (Figure 6) must be in the Off position to allow the
door to open. Turn the handle 90 degrees counterclockwise to the Off position
prior to opening the enclosure. The handle has a small arrow pointing to the
word Off. This disconnects the power from the source circuits.
For additional security, when in the Off position, each disconnect handle
supports lock out/tag out functionality with three locations to accommodate a
lock or tag with a shackle up to 1/4-inch in diameter.
Figure 6 Disconnect handles
On position
Off position
Lock out/Tag out
position
Multiple Disconnect Safety System Installation and Operating Instructions
950-001568-000 Rev A 20
Chapter 3: Installation Procedure
The handle of the enclosure door (Figure 7) has a tool-activated lock at the
bottom. Unlock with a flat-head screw driver. This releases the door handle. Lift
the bottom of the handle to release the latch and open the door. The door
handle also has an 3/8-inch eyelet to accommodate a padlock.
Figure 7 Opening the enclosure door
To securely close the door, press the handle completely down.
Opening the Dead Front
If the disconnect handles are located on the dead front instead of on the door of
the enclosure, you must first open the door (as shown in Figure 7). Then set the
disconnect handles to Off (as shown in Figure 6).
The dead front is locked at the top and bottom left corners using a bolt supplied
with the enclosure. Use a T30 Torx (or star) wrench to remove or install the bolt.
Release lock
Padlock location
Handle released
Latch released and handle open
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