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is a coordination study required at 120V? I never seen a coordination study done on a 120V lighting panel or 120V control panel. My Reviewing Engineer is asking for one on my control panel which is all 120V, and all the same 1489 circuit breaker type just with different amperage. I believe the...

All the breakers in my control panel have the same manufacturer. Amperage is different. So i ASSUME same trip curve.

@dpc if these breakers are instantaneous trip would not the branch experiencing the fault be the first to trip?

Coordination to them is ensuring the branch breaker experiencing the fault goes off first before the Main breaker. Is coordination even necessary at this low level? Typically the circuit breakers are in place to protect the wire/equipment. Yes this is a new PLC control panel. Even if I...

I have never been asked to do a coordination study on my PLC Control panel. I'm using various amperage of the same Allen Bradley Breakers 1489-A1D020 - 2 Amp 1489-A1D030 - 3 Amp 1489-A1D050 - 5 Amp 1489-A1D200 - 20 Amp These breakers feed power to I/O module,Power Supplies, and various...

client does not want to add a flow meter due to budget.

Had some help. Find the volume of the tank. One min later find the volume again. The difference would tell you have many gallons you lost or gained in a min sample or flow rate in Gallons/min.

I'm trying to find the formula for the inflow rate or outflow rate of a cylinder tank knowing the Volume. Look online and did not find much literature. Flowrate units should be Gal/Min.

I wish my I/O cards did. My project called for the 1794 Flex I/O family of module. Luckily I only have 4 modules. Do you know what the ANSI and Nema Standard requirement is for meggering/over-potential test in my case?

GroovyGuy, See attached specification. It silent on voltage range. I know 14 AWG wire insulation in my panel is only rated for 600V and the Belden cable I have is only rated for 300V. I might be just megger each and every wire in my panel. If I had known this sooner I would have megger/hi-pot...

One of my clients want me to Hi-POT my PLC Control Panel per their specification. I have never been requested this before on a PLC Panel. I'm pretty sure a Hi-POT will damage Electronic Equipment in the panel. Has Anyone done this before? Do you have to unterminate every wire end to end to do...

@ Skythian I understand what you are saying about limiting the FCT to 2 sec, but what if it was a bolted fault that occurred. The breaker would still not trip. I plan on making a recommendation anytime the Ie is high turn off genset for trouble-shooting/maintenance.

Is there a boundary that Arc Flash Labeling is exempt, like anything under 240V. In NFPA 70E 2012 it stated anything under 240 V was exempt from labeling, but this was removed in the 2015 edition. Is there another document/standard that can shed any light?

Thanks. If the generator is needed the client has to manual switch it on. Also the Generator is normally locked out. I will investigate which case gives me the highest IE.

When you print Arc Flash Labels it's typically in the Normal/Utility configuration? In my project I also have Standby Generator as well. I don't think they would want two Arc Flash labels. Ronne

I have met with the Client and informed me that I have now involved Hoffman Cooling/Thermal Engineer. At very best we can put the outside temp to 122°F(50°C) and an inside temp of 125°F and the Hoffman cooling analysis states we need a fan that can do about 400 CFM (overkill in my opinion), but...

In my Arc Flash Study Case I can limit the current to 2 sec. I'll state in my report that I clamped the FCT to 2 sec due to low calculated fault current or should I not mention it since this sounds pretty typical and the client will see my TCC curves and data anyways.

I have designed a simple control panel that has an internal heat load of 199 Watts. Its a 72x36x24 Hoffman Enclosure. This control panel is in a temperature controlled building. None the less the specification is requiring me to do a heat load calculation with an environment temp of 50°C. All...

When the System is on Utility Power no issue at all. I get low incident energy levels, since the Main_CB has a different type trip curve. For the mean time I will note and state my findings. If they Client wants to Invest/go another route I will go with your suggestion. Thanks again, R_Roc

I have conducted an arc flash analysis in Etap 14.1. I'm getting a warning message that states "Exceeds Max. PPE Arc Rating" I believe this is due to my bolted fault current or Ia (Arc Current) of 2.9KA. I have a LV (480VAC) Main CB Cutler and Hammer KD Series Breaker, with a Trip Device Part #...