Solo tengo curiosidad: ¿Alguna vez ha leído la norma IEEE 1584: Guía IEEE para realizar cálculos de riesgo de arco eléctrico? -Toda -Parte -No Haga clic para RESPONDER.
I was asked to evaluate some “newer” bus duct technology that are finger safe, use a turn and lock connection or similar methods without turning off the power. It seems to do a great job at significantly reducing if not outright eliminating the shock hazard. It also looks like the risk of causing a fault when installing or removing a module is reduced (eliminated?) as it seems it would be very difficult to short line to line or line to
Hi All. I know I’ve seen a picture or two of your typical oil filled pad mounted transformer that had fuses or a breaker installed right off the paddles on the secondary compartment. I tried googling it and could not find any. I’ve asked our ABB and Cooper reps if they offer and factory installed breakers or fuses and they both said “no”. Has anyone come across anything like this? I realize on the bigger sizes it may be very
Looking at the IE calculation there is a variable for grounding depending on what type system you have installed, and noticed that the grounding type can have a significant effect on the calculated IE energy on ungrounded vs grounded systems. Just curious if anyone can shed some light or point me in the direction of some literature that would better explain the cause of increased IE on ungrounded systems. I see the variable change in the calculations and there is
One of the forum member’s posts prompted this weeks question of the week. It is about grounding, more specifically – high and low resistance grounding. (some may use reactance grounding). Rather than having a solidly grounded system or a delta connected system, some will use a grounding resistor to limit the line-to-ground short circuit current that flows during a fault. This week’s question: Does your company (or clients) use grounding resistors anywhere in the power distribution system? No Hi Resistance
¿Cómo se calcula la corriente de funcionamiento normal de una carga a partir de la clasificación MCA, si es lo único que se tiene? Gracias. HAGA CLIC para responder.
Anyone ever heard of a preload indicating washer? Looks very simple. It’s a washer that crushes when the fastener reaches 80% of yield. According to Sandia Report SAND2008-0771 they are accurate to +/-10% of clamping force compared to +/-35% for a torque wrench and it directly measures clamping force unlike a torque wrench that is mostly measuring the friction being overcome by the nut heat and the threads. It appears that there are 3 versions. One has slots where you
Don’t mean to beat this topic to death. Well, yeah, I guess I do, but since I had another example of being over dutied/under rated come up today I thought I would share it. Scenario: Fairly low impedance (2.9%) 300 kva dry transformer originally feeding a large dimmer rack. Over the years someone added a panelboard off the secondary of this transformer plus a cam-lock quick hookup for a mobile TV broadcast truck. The branch panel is a Siemens S1
The duration of an arc flash can be greatly affected by the condition of electrical protective devices – i.e. circuit breakers, relays etc. NFPA 70E has been placing an increased emphasis on equipment being properly maintained. Has your company/client increased the emphasis on electrical maintenance as a result of 70E? Yes No Many clients – it depends CLICK to answer.
Hi all. I use SKM PTW on a daily basis but only have a single user license with a hardware key. I have a student worker (I work at a university) who mostly spends his time pulling old drawings and product data from our archives for me to work from. He also does some measuring of feeders and records them on the one-line and also goes out and applies the arc flash labels after I’ve done the study and printed
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