Electrical and Instrumentation NCRs on Projects
In this article we summarize some NCRs list which electrical and instrumentation QC Engineer raise during construction phase of projects. Electrical and Instrumentation “Repetitive” NCR’s from Previous Saudi Aramco Proiects or international Projects. Main keywords for this article are Electrical and Instrumentation NCRs on Projects, Conduit seal fittings installed where not required. Conduit and instrument air piping.
NCR means Non Compliance Report with company standards or international standards.
Electrical and Instrumentation NCRs on Projects
- Conduits routed across areas restricting access and egress and creating tripping hazards. SAES-B-054 requires that all means of access and egress be unobstructed.
- Omission of conduit seal fittings at boundaries separating hazardous from unclassified areas. NEC 501-5b2 requires that all conduits passing from a classified to safe area be sealed at the boundary. The necessity for many of these seal fittings can be minimized with a little planning by the design contractor. SAES-B-068 and API-RP-500 set the minimum requirements for classifying areas surrounding hazardous gas or vapor release sources. There is nothing
preventing the designer from expanding the hazardous area limits within process areas to eliminate gaps in the boundaries.
- Conduit seal fittings installed where not required. Saudi Aramco Standards prohibit installing seal fittings at locations where not required by the National Electrical Code. Unnecessary seal fittings create significant maintenance and operational problems and for wiring modifications where a seal fitting must be removed to access wiring.
- Cable trays inadequately supported. NEMA VE-1&2 have very specific requirements regarding the support of cable trays at fittings.
- Cables installed in conduits that have elbow type fittings with a bending radius smaller than the cable’s requirement .The NEC, IEEE 576, and Cable Manufacturers have specific requirements that limit the bending radius for different types of cable.
- Use of conduit fittings made from material other than cast/ malleable iron or steel. SAES-P-104, 8.9.1 requires that all conduit fittings, covers, flexible connectors, etc. shall be made of these materials.
- Electric motors that do not comply with environmental and nameplate marking requirements. 17-SAMSS-502 & 503, API 541, and IEEE 841 requirements for electric motors must be complied with.
- Conduit and instrument air piping supports attached to ladder side rails and platform handrails. Safety Standards prohibit using access ladder side rails, and the top and sides of elevated platform handrails for attaching supports for any utilities. 150 mm of clear space is also required on the sides and behind all access ladders.
- Conduit and instrument air piping supported from Process piping. Process piping shall not be used to support conduit or instrument air piping unless no other possible means of support is available. Even in these extremely rare cases, many restrictions apply, such as operating temperature of the pipe, vibration potential, etc.
- Cables in tray exceeding the loading limit requirements. QC and installation personnel must review NEC 318-5, 9, 10, 11, 12, and 13 requirements for strength and rigidity to provide adequate support for contained wiring; and the number of cables permitted in cable trays. Please note that all cables larger than 4/0 A WG as well as all cables rated 2000 volts or greater must be installed in a single layer.
- Direct buried cables routed under paved areas. SAES-P-104, 10.11 requires that cables crossing under paved areas and concrete slabs where extensive excavation would be required to replace a cable, must be run in duct banks.
- Direct buried cables installed in multiple layers. SAES-P-104, 10.14 requires direct buried cables to be installed in a single layer.
- Battery disconnect located outside the battery room and not equipped with under voltage release. SAES-P-103, 5.5.4 requires a two-pole circuit breaker with under voltage release to be installed on all battery systems. NEC 240-21a requires all conductors to be protected against overcurrent at the point they receive their supply (e.g. at the battery).
- Cable from transformer neutral to ground resistor run in metal conduit. SAES-P-104, 10.5 requires cables connecting transformer neutral terminals to grounding resistors to be installed in PVC conduit
- Aluminum cable trays penetrating masonry and fire-rated walls. SAES-B-008, 5.4 requires cables entering buildings to be through sealed conduit sleeves. SAES-M-100, 2106.1.9 prohibits aluminum penetrations through masonry walls. Most cable tray manufacturers recommendations advise against penetrating fire-rated walls with cable tray due to the difficulty in properly sealing around it.
- Sanitary Sewer Lift Station control panels that do not comply with requirements. SAES-S-010, 5.3.6 and 5.3 .7 have some very specific requirements concerning power supply, controls, and control panels for lift stations.
- Instrument nameplates tied on to instruments or supports with wire. Saudi Aramco Standard Drawing AD-036031 and SAES-J-700, 8.8.2 requires that nameplates be securely attached to the instrument or adjacent support structure with two stainless steel screws.
- Over-filled wireways and “sloppy wiring” in Marshalling Cabinets, Control Panels, Relay Panels, etc. NEC 362-5 prohibits wireways from being filled to more than 20% or their capacity at any cross-section of the wireway. Many times this can be attributed to craftsmen leaving excessive “loops” of wire in the wireways, resulting in huge bundles of excess wiring cluttering up wiring spaces and restricting access to terminal points.
- Instruments, local indicators, and level gauges not accessible and readable from grade, ladder, or platform. SAES-B-054, 4.2 and SAES-J-300, 4.1 requires all instruments and level gauges to be accessible; and operational requirements dictate that they be readable.
- Local Control Panels, ESD wiring, instruments, and air supply piping located in Fire Hazard Zones without being fireproofed. SAES-J-601, 11.1.2 and SAES-B-058, 8.5 require that ESD cabling, air supply piping, instruments, and other components of an ESD system inside fire hazard zones be fireproofed.
- Local Control Panel installed in hazardous locations with components not suitable for the area. 34-SAMSS-821,188.8.131.52 and NEC 500-3c & d require that all equipment located in classified areas be certified for the environment.
- Non-armored branch circuit supply cables installed beneath raised floors in cable trays. NEC 300-22c and 645-5d require non-armored branch circuit supply cables beneath raised floors to be installed in conduit or totally enclosed metal wireways.
- Electrical and Instrumentation violations on vendor fabricated Mechanical Equipment Skids. Contractors generally send mechanical inspectors to vendor’s shops to inspect compressors, pumps, boilers, etc. These inspectors are not trained in requirements for the electrical and instrumentation systems associated with the equipment.
Consequently, the first electrical inspector to look at these skids is the PID inspector on site. Violations that could have been easily corrected if identified in a timely manner would require extensive re-work to make the needed corrections, repeat loop tests, functional tests, and acceptance tests. Due to schedule restraints, we are generally forced to accept these sub-standard installations with waivers and concurrence letters.