For the 100-ampere services, 8 AWG copper grounding-electrode conductors are adequate. A 1/0 AWG copper grounding-electrode conductor may be run from the 200-ampere service to the metal water pipe grounding electrode. I assume the service conductors will be 4/0 AWG copper for the 200-copper service and 2 AWG copper for the 100-ampere services. The service conductors are two sets of 250 kcmil copper conductors with Type THWN insulation. What size grounding-electrode conductors are required for grounding a 200-ampere and three 100-ampere services? I would like to tap the grounding-electrode conductors from the three 100-ampere services to the grounding-electrode conductor from the 200-ampere switch. The 90☏ insulation increases the ampacity of 6 AWG copper conductors to 62. For increased ampacity without increasing conductor size, use Type THHW insulation. Read down the 75☌ column to 6 AWG copper for a corrected ampacity of 49 amperes. With a CDA slide rule, the table should be set on the 114☏–122☏ scale. For an ambient temperature of 91☏ with the conduit located 4 inches above the roof, the temperature in the conduit is listed at 121☏. The Fine Print Note following Section 310.16(B)(2)(6) recognizes these ambient temperatures. What is the corrected ampacity of three 6 AWG copper conductors with Type THW insulation run exposed to the sun and within 4 inches of the rooftop of a manufacturing building? The wiring method is rigid metal conduit.īecause the person asking the question is from Miami, we will use the outdoor temperature of 91☏ as shown in the Rooftop Ampacity Adjustment Tables provided by the Copper Development Association (CDA) with ambient temperatures for various cities taken from the ASHRAE Handbook. Dry-type transformers 600 volts, nominal or less, located in the open on walls, columns, or structures, shall not be required to be readily accessible.” Therefore, a ladder or permanent staircase is not required.
QT PLATFORM CONTRACTOR CODE
Transformers must be readily accessible to comply with Section 450.13 of the National Electrical Code (NEC), which states, “Accessibility: All transformers and transformer vaults shall be readily accessible to qualified personnel for inspection and maintenance or shall meet the requirements of 450.13(A) or 450.13(B).”īut Part (A) of 450.13 allows this installation without providing a ladder or permanent steps to the platform. My question concerns whether the transformer has to be readily accessible or is a permanent ladder to the platform required. Is a 75 kVA dry-type transformer with -primary voltage of 480Y/277 volts and secondary of 120/208 volts considered to be readily accessible where the transformer is located on a platform 8 feet above the floor? The platform is large enough to provide working space around the transformer. It also may be necessary to provide oxide inhibitor and wire brush the wire before making the connection. Wire connectors should be marked “AL-CU intermixed-dry locations” and be installed in accordance with the manufacturers’ instructions. Where there is adequate space in the enclosure, copper pigtails can be connected to the aluminum conductors and the copper wires can be connected to the AFCIs. I am not aware of any combination-type AFCIs that have terminals suitable for aluminum conductor terminations. The planned subcontracting effort is ten person months and we wish the subcontracting could be started already in December 2017.Įxpertise with the following Qt concepts is required.Article 210ěranch Circuits Article 240 Overcurrent Protection Article 250 Grounding and Bonding Article 310Ĝonductors for General Wiring Article 450 Transformers and Transformer Vaults (Including Secondary Ties) Article 480 Storage BatteriesĪre any combination-type arc-fault circuit interrupters (AFCIs) available for connection to aluminum branch-circuit conductors? In addition, fluent English skills are needed to co-operate with other R&D teams in Norway and Finland. The candidate would work as a sub-contractor in a close co-operation with the Qt Creator team, located in Berlin. Connected features improve the developer workflow, by allowing developers to share Creator data between several work stations, for example. We're looking for a Qt expert to help us implement new features in Connected Creator. Qt is a C++ based framework of libraries and tools that enables the development of powerful, interactive and cross-platform applications and devices. The Qt Company ( qt.io) is responsible for Qt development, productization and licensing under commercial and open-source licenses.