Anderson Power Products says connectors designed for 400V DC are coming into their own for single-phase AC
Connectors designed for high voltage DC use are being adopted for AC distribution, prompting Anderson Power Products to produce a version of its Safe-D-Grid connector for single-phase AC applications.
The Saf-D-Grid 300 is based on the Anderson’s 400V DC Saf-D-Grid connector, with the same contacts, insulators and safety systems, and came about because the company noticed that its customers were using the DC products in AC applications where higher voltages are being used for increased efficiency.
While direct current (DC) has been suggested as a more efficient path for distribution in data centers, it seems that alternating current (AC) is still the norm, and can benefit from safety systems designed for DC.
Saf-D-Grid 300 connectors
Source: Anderson Power Products
Plugging on with AC
“Our Saf-D-Grid for 400V DC is being broadly adopted as the power inlet connector for Higher Voltage DC (HVDC) information technology equipment,” said Rick Loveless, senior product manager, APP. ”We noticed that many top tier original equipment manufacturers are also choosing Saf-D-Grid for applications requiring a 120V to 277V AC power inlet. The higher power capability, compact size, and integral latching features are well suited to the industry trends of increased rack density and use of higher voltages for efficiency.”
The AC product uses the same silver-plated copper contact as the DC version, with durable thermoplastic insulators. Configurations allow up to 30A and 300V within the same panel cutout as IEC 60320 C13 / C14 connectors.
For some years, it has been suggested that data centers can save money and operate more efficiently by moving to DC instead of AC, eliminating equipment and unnecessary conversions. In 2007, one of the earliest studies of 400 VDC distribution was presented at the International Telecommunications Energy Conference and concluded that DC power distribution can achieve efficiency gains of 7 percent versus AC distribution.
In 2010, a case study by Intel and EYP Mission Critical Facilities found that a 5.5 MW data center could get energy savings of 7 to 8 percent by using 400 VDC instead of high-efficiency, best-practice 208 to 480 VAC. The center would also save 15 percent of the capital cost of its electrical equipment and 33 percent of the space it took up, while getting a system which would be three times as reliable as the AC option.
Vendors have responded and 400 VDC IT equipment is now available from a growing number of IT manufacturers, including Cisco Systems, HP, IBM, Juniper Systems, NEC, and SGI.
Despite this, data center operators have been reluctant to switch, and one main roadblock has been safety. AC voltages ramp up and down, passing through zero, while DC systems have a constant high voltage, increasing the amount of energy that can dissipate through arcing, potentially damaging equipment and hurting people.
Traditional IEC320 AC power connectors cannot survive the breaking of a 400 VDC arc nor do they protect the user from the DC electric arc, so vendors in the field have developed products that greatly minimizes the DC arc, while the deep, overlapping housings protect the user from any exposure to the electric arc. The products are designed to offer connectors that are touch-safe when mated or unmated and include an integral safety latch for further user safety.
Safety conscious operators unwilling to move to DC haqve noticed that these connectors could improve safety on AC systems, with their extra protection for users, and an ability to withstand arc breaking for hundreds of cycles.
The Saf-D-Grid 300 features separate mechanical keys for 10A and 20A configurations which prevent accidental overloadicng of wires not rated to carry that current. The product also offers higher operating temperature than connectors which are limited by use of brass contacts. The maximum operating temperature of 80˚C makes Saf-D-Grid ideal for power supplies where the hot exhaust is directed onto the power inlet connector. The receptacle housing is constructed of high temperature glass-filled nylon allowing it to operate in temperatures of up to 120˚C.
Both the plug and receptacle side are touch-safe to maximize operator safety at hazardous voltages. Universal touch safety also enables the simplicity of using the same receptacle for both power inlet and outlet connections. The integral latch on the plug housing prevents accidental disconnect of power without the need for added accessories such as metal bail latches or hook & loop fabric straps. An optional ground-tied shield is available to minimize the EMI profile of power supplies.
Would you consider Higher Voltage DC distribution in your data center?