Transcript Session Number & Title

PAC 1.2
Disaster Avoidance in a Digital World
Power & Systems Innovations of Tampa, Inc.
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Data Center World – Certified Vendor Neutral
Each presenter is required to certify that their
presentation will be vendor-neutral.
As an attendee you have a right to enforce this
policy of having no sales pitch within a session by
alerting the speaker if you feel the session is not
being presented in a vendor neutral fashion. If the
issue continues to be a problem, please alert Data
Center World staff after the session is complete.
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Disaster Formula, Easy, Simple & Cheap!
Lack of Planning + Assumptions + Minimal
Standards + Poor Execution + Lack of Installation
Verification + Improper if any Maintenance (fix it
after is breaks) =
Disaster waiting to happen!
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Assumptions (AKA: Famous Last Words)
The facility grounding is low resistance & Impedance.
All facility ground bonding was completed properly to best industry standards.
The lightning protection system was properly installed to best industry standards.
The lightning protection system is fully functional.
The lightning protection system grounding is properly installed.
The lightning protection system grounding is low resistance & impedance.
My surge protection is proper & adequate for the exposure & risk.
My surge protection was properly installed.
My surge protection is fully functional.
My power distribution system is properly installed.
We don’t need up to date “as built” plans of our facility.
My power distribution system has not been inspected, scanned, tested & serviced.
My PDU’s are properly installed.
Equipment bonding by my vendors is always completed properly.
I do not have an installation standard my vendors must follow.
No one inspects vendor workmanship.
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Facility Grounding
& NEC Article 250
NEC Article 250 – Not a proper standard for any facility.
The NEC allows for high resistance grounding.
The NEC will allow for a 1,000+ Ohm ground (no limit).
The NEC is a minimal life safety standard.
The NEC doesn’t address is sensitive equipment grounding.
The NEC does not consider temperature effects on resistance.
The NEC does not consider grounding impedance.
The NEC does not consider soil conditions.
The NEC does not require testing after the installation is finished.
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NEC 250-56
“A single electrode consisting of a rod, pipe, or plate that does
not have a resistance to ground of 25-Ohms or less shall be
augmented by one additional electrode of any of the types
specified by 250.52(A) through (A) (7).”
NOTE: You never need to measure to meet the 25-Ohms or less if
you install two 8 foot long ground rods and bond them together per
the NEC!!!!
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This is code compliant grounding!
(I hope it does not look familiar!)
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Have any like this?
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How about bonds like this one?
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Read your owner’s manuals.
Most sensitive equipment manufacturers outline some
grounding, bonding or isolation standards (if required
for their equipment). In part to protect them in event of
equipment failure during the warranty term.
If the manufacturer outlines this to protect themselves.
That should be your notice to protect yourself and get
the grounding, bonding or isolation to meet or exceed
their requirements.
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Seasonal Change Will Impact Grounding
•Shallow earth grounding in locations where the ground temperature will be below freezing
is improper.
•Some areas of the continental USA have a frost line from 3 – 6 feet or more.
•How well does your 30” deep counterpoise work when the ground is frozen to below 30”?
•How well do your 8 foot ground rods work when in soil frozen to a depth of 6’ or more?
•Lightning does occur during snow storms and in the winter.
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Grounding Systems Should be Designed
•Grounding design must consider all factors that will effect the performance
of the grounding system.
•Included will be the “earthing” design, the Ufer bonding design along with
the buildings basic construction & function.
•Geographic location, weather conditions, wet climate, dry climate, soil
resistivity, site conditions, site restrictions, building design, etc. all impact
the design of a sustainable grounding system.
•Anything less is not sustainable and the grounding will not be something
you can rely upon.
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Impedance & Lightning Energy
•Lightning is broad spectrum energy.
•Lightning has low & high frequency elements.
•Impedance is the measure of the opposition that a circuit presents to
a current when voltage is applied.
•High impedance grounding paths translates to lightning not going
where you want it to go, to the earth, away from your facility and
everything inside of it.
•If the path to earth ground is high impedance much of the lighting
energy will not be dissipated to earth as it would be if the path were
low impedance.
•Lightning energy that is not dissipated to earth will enter a facility
and most likely be the source of damage.
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(Ground) Bonding Basics
Ground bonding is required for life safety.
Ground bonding is required to provide a path to the earth to
reduce overvoltage from lightning (NEC).
Ground bonding is to be a low-impedance fault current path
back to the source of the electrical supply so “over current”
devices will function properly in event of a ground fault.
Ground bonding is required by the FCC (NEBS and GR-3160)
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What is Bonding?
Bonding (Bonded). The permanent joining of metal parts to form an
electrically conductive path that ensures electrical continuity and the capacity to
conduct safely any current likely to be imposed.
Bonding (IEEE Std 1100-1999).
Bonding is the interconnection
of conductive parts for the purpose of maintaining a common electrical potential
and to provide an electrical conductive path that will assure electrical continuity and
the capacity to conduct safely any current likely to be imposed.
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High Performance Bonding
•Never use solid wire. Always use stranded wire, high flex is best.
•Home run the bond from all exterior services or devices.
•Never daisy chain ground bonds.
•Always use double lugs.
•Never use dissimilar metals for bonding.
•Protect bonds with conductive grease.
•Use stainless Nylock bolts, nuts & flat washers.
•Option: Stainless flat washers, lock washers, bolts & nuts.
•Torque connections to the maximum of the hardware rating.
•Always remove paint from the metal before bonding.
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What is wrong with this Picture?
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What is wrong here?
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How about here? Code Compliant?
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What do you see wrong here?
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Do you see a problem here?
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Ground System Testing
•Your ground was tested when and by whom?
•Do you have the test results in the form of a report that outlines the conditions the day of
the test, the calibration date of the test equipment?
•What were the weather and soil conditions when the testing was completed?
•Ground testing should only be performed by a trained, factory certified, and highly
experienced technician (minimum 5-years).
•The testing should be with a test equipment that is adequate and proper for the conditions
of the site and will yield accurate test results.
•A detailed written record should be kept of every test from the date of the first test after the
grounding system was installed.
•The data from all test should be compared.
•Most (over 95%) of those testing grounding systems have never been properly trained to
use the test instrument as it was designed to be used.
•Most (over 95%) of those testing grounding systems do not have test equipment that is in
current calibration.
•Most (over 95%) of those testing grounding systems will not provide a written report that is
accurate and can be relied upon.
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Surge Protection Devices (SPD)
•How much surge protection is proper?
•How are SPD rated?
•How should SPD be installed?
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How much surge protection is proper?
A minimum of four (4) layers of SPD is recommended.
•The first SPD on the “normal” side (utility feed) should be installed on the
utility side of the transfer switch input.
•The first SPD on the “emergency” side of the transfer switch should be
installed on the generator feed input to the transfer switch.
•The second layer of SPD should be ahead of the main breaker (means of
disconnect) as close as possible to the grounding system bonding point.
•The third layer of SPD should be installed on every panel that supports
outside loads of any type. (This is to be augmented by series SPD on high
exposure circuits.)
•The fourth layer of SPD is to be on the critical panels & disconnects. This
will include the input disconnect of each UPS.
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How are SPD rated?
Valid for Safety:
UL-1449 R3.0 for safety.
Valid for Performance:
NEMA LS1 1992 Performance Testing Requirements. (The current version of this
standard does not require “performance” testing.
Common:
Buy mine, they are the best, because this is what I sell!
Best Advise:
Don’t do this alone. Find someone with significant experience, a long term success
record (more than 10-years) that can be verified. Simply put, find an expert to help
you.
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How should SPD be installed?
SPD are most often installed parallel in the electrical system. Therefore:
•Panel SPD should be on the feed end of the panel as close as possible to the neutral connection.
•Mounted on the side of the panel with wires going strait to the circuit breaker.
•If protected by a circuit breaker, it must be 100% rated.
•Installed wire length is critical, short as possible, no excess wire.
•Low impedance conductors are preferred where possible.
•Conductor type and size is critical, stranded & larger is better.
•Sharp bends are wrong, no 90° turns.
•Wires should be twisted 4-6 turns per foot (it lowers the impedance).
•Installation must conform to best industry practice. (Meet IEEE guidelines, etc.)
•SPD MUST NEVER BE MOUNTED INSIDE ELECTRICAL PANELS.
•Fire stop and sealant must be used in the conduit that connects SPD.
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SPD are installed, now what?
•In the worst case event SPD are sacrificial devices.
•In most cases SPD will function and if the event exceed their rating reset.
•Worst case the SPD will sacrifice itself to protect the down stream
electrical circuits and devices.
•SPD should be inspected & tested a minimum of annually.
•In event of a “utility event” or a direct lightning strike SPD should be
inspected without delay.
•A minimum of one employee should be trained to inspect and test SPD.
(Or have a professional do it for you.)
•The facility should have the required test equipment on site and in current
calibration.
•A detailed record must be kept of all SPD testing to determine any trends
or changes in the state of protection.
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Facility Power Distribution
•Oversized circuit conductors prevent voltage drop issues.
•Facility power distribution designed and installed to the minimum standards of the
NEC is a recipe for ongoing problems.
•Load that are inductive contribute to power quality issues.
•Sensitive loads should not be on the same panel as inductive, dirty or devices
that use the ground conductor as the current return path.
•Outside circuits are a back door for lightning energy.
•Building steel can be the source of lightning damage.
•Wiring practices including location of conduit is very important.
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Circuit Wiring
- Formula for success
•Segregate loads. Sensitive loads on their own panel(s).
•Us only harmonic-rated bolt in circuit breakers.
•Use panel boards with 2X Neutrals feeds.
•Oversize phase conductors, on all circuits, it is green and saves energy as well.(I²R
Loss Rule)
•Use only Harmonic rated transformers and PDUs.
•No shared conductors, home run phase, neutral and all ground conductors.
•Isolated grounds for all sensitive and critical 120VAC loads.
•Oversize conductors and at a minimum fully rated conductors that exceed the 5%
voltage drop standard.
•True IG ground bonding paths.
•Proper wiring is a 1-2% add on in the construction of most facilities.
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Oops, what about the low voltage SPD
The time allow today would not allow the subject to be covered
properly. Low voltage SPD should be a very high priority in your
“need to get it right” list.
Low voltage SPD will impact your data operations, life safety
systems, security systems and communications equipment.
I will be available after the session to answer individual questions.
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7 Key Things You Have Learned During this Session
1.
2.
3.
4.
5.
6.
7.
Your grounding must be inspected, tested & maintained.
Your lightning protection system must be inspected, tested &
maintained.
You need to verify your bonding is compliant with best industry
standards.
You need to establish installation & bonding standards for your
vendors.
You should review, inspect and test your SPD installation.
Your power distribution design & installation should be reviewed.
You should learn more about low voltage SPDs.
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Thank you
Power & Systems Innovations of Tampa, Inc.
Phone: 407-340-7621
Email: [email protected]
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