Frequently Asked Questions about Rack PDUs
How can Vertiv Geist deliver customized products in 1 week when others take months?
Vertiv Geist has the largest in-house engineering department in the industry. The in-house engineering department includes mechanical, electrical, conformance, board layout and software specialists. The testing lab at is authorized to conduct UL® testing on Rack PDU products to 60950 IT equipment standards as part of the UL® Data Acceptance Program. Our software specialists can create software for new or custom products and deploy directly to production to reduce lead times. There is also an in-house team responsible for embedded circuit design, which allows for faster turnaround on custom applications requiring circuit boards. The engineering team is dedicated to providing the highest quality products and service available in the industry and invests in continuous improvement. The Metalworks division allows us to punch, bend and paint our own metal products. This allows Vertiv to reduce already short lead times by eliminating scheduling conflicts with suppliers. The Metalworks team also helps reduce the lead time on custom units, making products available to the customer faster than anyone else in the industry.
What rating should I use to correctly select an rPDU for my installation?
There are several factors to consider when selecting a Vertiv Geist rPDU to ensure that the rPDU has sufficient capacity for the intended application. The three main factors to consider are (1) nameplate rating, (2) receptacle ratings, and (3) internal breaker configuration. NAMEPLATE: The nameplate rating marked on the rPDU is the intended operating voltage range and maximum operating input current. Nameplate ratings are based on both regulatory requirements and design factors and represent the continuous total current that the rPDU will be able to deliver to a load. The rPDU should not be installed in an application where the nameplate ratings are exceeded. RECEPTACLE: The rPDU’s output power is connected to information technology equipment through either NEMA or IEC receptacles. The rPDU should not be installed in a manner that will exceed the maximum current rating of any individual receptacle. For example, a NEMA 5-15R receptacle should not be loaded to over 15A regardless of the nameplate rating of the rPDU it is installed in. INTERNAL BREAKERS: The rPDUs can be equipped with internal circuit breakers that are used to protect the circuit in case of overload or earth fault conditions. For rPDUs rated 12A or 16A, the circuit breakers are optional components that act as supplementary protectors. For rPDUs rated higher than 16A, the circuit breakers are required components that provide primary overcurrent and earth fault protection for the rPDU’s internal circuits. The rPDU should not be connected to a load that will exceed the current rating of an internal breaker. For maximum protection against nuisance tripping, it is recommended that internal breakers are only loaded to 80% of the breaker current rating.
Can I purchase an rPDU without a circuit breaker?
Yes, some configurations can be purchased without an internal circuit breaker. All Vertiv Geist’s rPDUs require an appropriately sized branch circuit breaker in the building installation. Branch circuit breakers should be sized according to the rPDUs namplate rating, and electrical code requirements. To comply with the NEC the circuit breaker in the building installation should have a trip current rating that is 25% higher than the rPDU’s nameplate. For example, a 16A rated rPDU requires a 20A circuit breaker.
How do I determine how much power is needed in a cabinet?
Perform the following for a quick estimate of the power needed in a cabinet: Add the power ratings in Watts from the nameplate labels of the equipment you want to put in the cabinet. [Sometimes, the labels indicate Amps instead of Watts. In this case, multiply Voltage and Current values to get an approximate value for power.] Example: 30 servers each using 300 Watts= 30 x 300 = 9,000 Watts or 9kW.
Why are Vertiv Geist cord-connected units listed with a de-rated Amperage?
Cord-connected rPDUs carry a nameplate current rating that is 80 percent of the branch circuit rating listed in the catalog specification. The nameplate current rating has been lowered in order to comply with UL®/NEC requirements. Vertiv Geist rPDUs are UL® Listed as Information Technology Equipment to the UL® 60950 Standard. UL® 60950 requires that the attachment plug of Listed Information Technology Equipment shall be rated not less than 125 percent of the Rated Current of the equipment at the nominal system voltage range as defined by the configuration of the plug. This clause in UL® 60950-1 is based on the requirements of the National Electrical Code (NFPA-70), which state that branch circuit conductors and overcurrent protection devices shall be sized to carry 125 percent of the continuous load and 100 percent of the non-continuous load on the circuit breaker. Due to this UL®/NEC requirement, the nameplate current rating of an rPDU is 80 percent of the maximum current rating of the branch circuit used to power the rPDU. Most of our customers base their rPDU input current specifications on the branch circuit ratings; consequently, the catalog lists the ratings of the branch circuit that the rPDU is intended to be connected to. In addition to the branch circuit rating, it is important to consider the nameplate rPDU rating which includes the 80 percent de-rating factor required by UL®/NEC when calculating rPDU requirements.
How does Wattage relate to heat in a cabinet?
Heat is measured in BTUs and power is measured in Watts. Almost all electrical energy used in computing is converted to heat. An IT equipment power supply can be as low as 80 percent efficient. This means that for every 100 Watts it draws, 20 Watts may be converted directly into heat without ever being used by the device. As the IT equipment processes information, the rest of the power is dissipated throughout the system as heat. Since all power can be counted as heat, adding the Watt ratings of all equipment in a cabinet will give a relatively 1:1 relationship to heat generated. Example: 40 servers x 300 Watts each = 12,000 Watts (12kW) heat. Also, Watts can be converted to BTUs by multiplying Watts by 3.412.
Why can’t I output 120V from a 208V single-phase input?
Vertiv Geist rPDUs are high quality power strips intended to be used to distribute power to information technology equipment within a data center. These rPDUs, which are available in single or three phase configurations, are not designed to increase or reduce the input circuit’s voltage level. Single-phase 120V rated power distribution units installed in North America will typically be powered by a 120V line-to-neutral circuit. The outlets on these rPDUs will all be wired line-to-neutral and will output 120V. Single-phase 208V rated power distribution units installed in North America will typically be powered by a 208V line-to-line circuit. The neutral conductor is not connected to a standard 208V single-phase rPDU; consequently, all outlets will be wired line-to-line and will output 208V.
What are the advantages of bringing 3-phase power to my cabinet?
Less wire under the floor improves airflow and reduces wiring confusion. A 20A 3-phase installation contains five wires where the equivalent single phase system would require nine wires (3x3). 2) Fewer whips to pull saves you time and money. A 3-phase system has one whip for the electrician to bring to the cabinet where the equivalent single phase system would have three whips. This saves both material and labor cost. 3) Simplified load balancing reduces technician installation and troubleshooting time. With all 3 phases available in a single cabinet, load balancing can be achieved at the cabinet level where similar type equipment is often found. In a single-phase system, a minimum of three cabinets may need to be examined to balance the same load.
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From basic PDUs, to monitored and switched rack power distribution units, to locking receptacles, Vertiv’s solutions will offer the power distribution you need, as well as remote monitoring and management of your assets' power usage, so you can rest assured everything is running at peak performance.
Use the rPDU Finder to locate the Vertiv Geist power strip that you require based on a variety of configuration options. If you cannot find the rPDU you need in our list, please call for assistance; delivery of non-standard units can be fulfilled in as few as 7 days.