Power Audit & Component Selection Guide

• The document outlines the process for performing power/circuit audits and component selection for site retrofits and greenfield sites.
• It describes how to conduct a power audit, calculate total site power draw, and select equipment for building a DC power plant.

Pre-Inspection

• A site visit is conducted to complete a retrofit/co-location/green site inspection sheet, looking for proper power, grounding, environmental systems, tower space/mounts, and cabling.
• The current devices are identified from PQ, and each cable at the switch is labeled.
• Taking detailed pictures and reviewing rack space help determine additional equipment or cabinet/rack needs.

Power Draw Calculation

• Calculating the current loads and any additional power needs and determining the best native voltage and polarity is essential.

Circuits Review

• Calculating the current circuits and additional circuit needs to determine the size of converters needed for non-native voltage and polarity equipment.
• Decommissioned equipment and radios are also identified.

Assemble Spreadsheet

• Data collected from the previous steps is used to build a spreadsheet, which serves as a tool to assemble the required equipment for the build/retrofit.
• The rectifier plant/power supply and distribution panels are selected.

Equipment Selection

• The selected equipment is documented in the spreadsheet tabs (Power and Eng. Summary), including serial numbers and circuit assignments, it uses the ICT and Packetflux distribution panel templates to identify each circuit.
• The voltage, polarity, and breaker/port connections on the distribution panels are noted.

Programming

• Jumpers (Packetflux) are placed using the Power tab in the master spreadsheet, and the distribution panels are programmed to match the Power spreadsheet.
• The rectifier plant/power supply is programmed using the programming guide for the selected device.

Pre-Install Prep

• Power and circuit components are pre-built, including all power and grounding cables, with circuits labeled with device identification and voltage/polarity for a quick switch over.
• All components are boxed and ready for installation, with two spreadsheets inside to be left on site.
• Final inspection sheet is required to test all systems and confirm nothing was missed.
• A final inspection sheet is required, especially for greenfield sites before customer release; for retrofits, this inspection occurs during or after the switch over.

Determining Current Load

• Log into the UPS and select In/Out Parameters to determine the current load on the system.
• For sites with multiple UPS units, add their power usage together.
• Add power requirements of new equipment (LTE, Tarana, Nokia units) to the current load to project the total watt load, the total site load at MTA is specifically mentioned as 9.4 amps at 120V and 986 watts.

MTA UPS Units Voltage Determination

• Determine the number of devices that are 48V, 24V, and 120V (convert to DC if possible).
• Go to Prequal Devices and PQ site list to cut and paste device information into a worksheet for power and equipment audits.
• Determine voltage for different devices: UBN=24V, UBNT Air Fiber UAF=48V, Dragon Wave DWN=48V, Cisco switch CSW=48V or 120V, SIA=48V, NOK=120V (converting to 48V).

Circuit and Wattage Planning

• Determine the number of circuits needed for each voltage and their respective wattage.
• Account for fan and cooling unit loads, especially for outside cabinet sites.
• Consider adding new devices to the chart.

Conversion to DC and BBU

• Convert AC-powered equipment to DC when possible.
• The large Nokia Airscale BBU unit can power 4+ sectors.
• Use the DC Rectifier system specs: 1570 watts of power with 8) 24V and 13) 48V circuits. For the 24V power use 48v-24v inverter with 10 amps. Add a 40% buffer for future growth to 628, a total of 2198 watts @48V.

ICT Unit Sizing

• Size the ICT unit by connections and power draw, an example provided stating units come in 700 or 1500 watt @48v.
• It mentioned that 3 700-watt rectifiers are needed to reach 2100 watts.
• Size the rectifier shelf unit and consider the number of rectifier slots. Use a rectifier plant with 12 circuits built in and 4 slots to provide 2800 watts, allows covers 12 circuits at the native voltage and polarity and bigger sites are mostly negative -48 as native voltage and polarity.

Distribution Panel Selection

• Select a distribution panel based on the known 8) 24V and 13) 48V circuits, plan for future growth in circuit number is essential.
• ICT panels typically come with 12 circuits per panel and can offer dual bus panels with 6 circuits on each bus (for one 24V and one 48V).
• For example, using a 12 circuit Distribution panel for 24V (powered by a 48-24V inverter) would provide 4 extra circuits, and is using the ICT-2U4 for 48V connections, the 48V connections would provide 12 circuits with up to 2800 watts, install 4 rectifier units to get 2800 watts, the remaining circuits can connect this shelf to a distribution panel with 12 more circuits, total of 24) 48V and 12) 24V circuits, and 12 circuits in the rectifier plant are -48v.

Cabinet Type

• In single-door Cabinets, use the front access ICT distribution panel with 8 circuits.

Power Equipment

• Rectifier Shelves and Power Supplies – are used for large power systems over 400 watts.
• LTE – Tarana sites needs approximately 2800 watts minimum.

Cabinet Type specifics

• If an outdoor cabinet is used, then the cabinets Rectifier plant is used, options include Emerson – Samsung/Texon cabinets or BDP - Purcell cabinets.

Vault Specifics

• For indoor vaults using the ICT rectifier shelf with 2800 watts (700-watt rectifiers), you can increase capacity up to 6000 watts (1500-watt rectifiers).
• The ICT – 2U4 - 2.8k (4-700 watt rectifiers) with 12 port distribution built in.

Additional Equipment Types

• ICT 2U4 with 4/700-watt rectifiers w/12port distribution and ICT 12 port distribution panel.
• Other Large Sites: 800-9000 watts, For the big sites we use the 2U4 as above as well a 2U6 for special applications with up to 9000 watts.
• Raging wire 2U6 with 1500 watt rectifiers can power a Nokia 7750 SR-7 switch with 100 amp breakers.
• Can use various ICT power shelves for smaller sites as well as their Platinum power supply with built in battery management.
• All negative 48V systems are used – smaller sites can use a Power supply instead of the shelf unit/select a PS unit and distribution panel, PS units sizes from 800 to 1600 watts are available.
• Bridgeway ICT with 3 rectifiers and dual bus panel all running utilizes 48V giving approximately 2100 watts and 12 circuits, it's used for radios on hybrid AC power sites + dual UPS and dual power supplied main equipment.
• Power Supply Selection –Can use these for smaller sites that would not exceed the max power draw of these units with future expansion built in. We use the platinum units that include built in battery management that includes charging and LVD (low Voltage Disconnect).

Power Supply Usage Notes

• Best for DC site conversions that have lower power needs and limited expansion, it can replace Shelf rectifier system for smaller sites.
• Be wise when deciding on sizing, adding additional rectifiers is not optional. 800 and 1600 watt for both 48 and 24 volt systems are offered.
• Sonora 02 with 1600 watt PS and 12 port ICT Distribution panel and 16 port Rack Injector are available. This configuration has has 28 circuits with -48, +48 and +24v.

Site Retrofitting Sheet (Example)

• Complete grounding and bonding need to be done on Site #224 Mount Akum
• Clean up and remove old wiring and cables on the roof.
• Install all new cables except for recently installed ones.
• Install new cable pass through in wall and run all cables through this.
• Replace wet batteries with AGM new 48V design with matching battery rack
• Upgrade to 1 ICT MPS Ultra Rectifier Shelf w/12 distribution, Two Distribution Panels. 48V to 24V inverter.
• Install MCT Surge unit with POE Power injectors for radios where necessary.
• Replace partially damaged Cisco Switch with Nokia unit.
• Confirm if equipment is installed/added. Update Future equipment list.

This guide details how to perform power/circuit audits and select components for site retrofits and greenfield sites. It covers conducting a site visit, calculating total site power draw, and selecting equipment for building a DC power plant. It also reviews circuit requirements.