I'm here from the 100 Days of Article 100. I already watched this video, but i can't recall any of the information. Watching it a second time will probably help.
I always ordered & stocked 200 KIC on our 250 & 600 volt fuses 1 to 1200 amps just to be safe. At a large candy company that I worked at in the 1980 ' S they used renewable link fuses on everything on 480 volt equipment. A lot of 30 & 60 amp dafety switches were feed from 3000 buss duct. Little by little I got rid of the think they were only good for 10 KIC renewable fuses.
I'm enrolled in an electrical training program and we're watching the training DVD you were on with Mike Holt as part of the course. Glad I found your YT channel Ryan
Watching wire jump at high current solidifies the reason we torque, pull, loose, tighten…. terminals. Imagine a dead short on a branch circuit and the impact of a wire jump in the panel causing a wire to separate from a terminal or along an attic beam. Very interesting Ryan - thank you.
Definitely hope I can get labels on my two inside panels before inspection on Monday. I put AFC on service disconnect but not the other two. Also I found the AFC for my service on the line drawing of the plans.
Here in Miami some inspector have had me find out from the utility company in writing because the plans did not show. Had to get the right breaker for the afc
Excellent presentation Ryan. I highly recommend this to anyone who is looking for help on this topic. I am sure it took an immense amount of preparation
At a very large hospital that I retired from while contractor was performing yearly cleaning & testing of 200 to 1200 amp 480 volt circuit breakers boss had us remove 6 or 8 spares from basement switchgear that had 40 or 42 KIA rating to a switcgear room on 10 th floor that all breakers were rated 65 KIA. We installed the spare 40 or 42 KIA breakers to what was all 65 KIA and never questioned it. Sharp Contractor picked this
In the example of the 300 KVA transformer at @18:41, you couldn't use the primary fuse of 80 amps on the nameplate to calculate fault current? I get 3600 amps if multiply 12470 x sqrt(3) x 80 / 480. But maybe they don't allow that because fuse might not blow in time, or weld itself together, or arc across the blown fuse etc. Still 3600 amps of 480v is one hell of an arc flash, enough to give someone being dumb the floor temperature challenge.
Do you know if there is any short circuit current requirement for splicing connectors like the Wagos or the 3M Scotchlok? I have not found information about it, it seems to me that the connectors are very useful but not in industrial buildings where the short circuit currents could be considerable.
I will see what I can find out, but I would guess the rating is quite high. If you think about a terminal block (power distribution block), for example, the part that fails during a fault is not the terminal but the way the terminal connects to the plastic and the plastic connects to the enclosure. The fault doesn't melt the terminal, it rips the insulating material off the terminal or off the enclosure. I just don't see many failure points on the connectors you mention (but that is me speaking without looking into it deeper).
Another great vid Ryan. Question at a 12 story building that I worked at all motors 5 HP & higher had VFD drives except for soft start on 200 HP soft start fire pump. Motors 60 HP & larger were on 18 pulse drives would this effect the motor thing on the Eaton calculator?
Great video. Is it code compliant to use fused disconnects upstream of equipment for short circuit protection on equipment with lower fault withstand ratings or is that not complaint with 110.10.
@@RyanJacksonElectrical thanks. Yeah this EV charger manufacturer only has an equipment rating of 5ka. Which basic is nothing. Just thinking of using peak let thru curves to show it is below 5 with a fuse. Thx
Thanks for the great videos! I have seen the after effects of cables jumping out of cable trays but never seen it before and dang that was cool!!!! I have never though of it as a magnetic issue causing it, just as a flow of electricity like water hammer.
21:56 i kinda wonder why i got 26,544 amps for the fault current on the 750KVA, 3 phase 480volt secondary, 3.4% impedance example. i did 750kva ÷ 831 ÷ 0.034 = 26,544 amps
Great point. My example includes the 10% transformer impedance variation that I discuss while using the software. I really should have included that in the written narrative of the example.
@@RyanJacksonElectrical I think i figured out what you are saying. 750,000VA ÷ 831 ÷ (0.0306 which is 90% of 3.4%) = 29,494.35A available fault current.
I'm confused. The future you are from say from t he transformer secondary the available short circuit current goes down while if I have it right from a long ago safety class the Arc Flash can be higher further from the transformer. Thanks for another informative vid.
The available fault current decreases the farther you get from the source. The incident energy is based on the voltage, available fault current, and (perhaps most importantly) the clearing time of the overcurrent device. Lower levels of fault current yield greater clearing times so the incident energy will vary greatly throughout the system. You really cannot just say that the incident energy will decrease the farther you get from the source.
@@RyanJacksonElectrical Thanks Ryan. Believe most electricians are more concerned about the Arc fault value in an existing large industrial setting to make sure they have the proper PPL. Diappointing to see most switchgear & panel boards still not labeled for Arc Flash rating. At the large hospital/research centets/ ambulatory building we took turns walking a company that wrote down every transformer and the panels they feed along with wire size and length of wire. Probably took over 60 hours over several months. After all said and done nothing got labeled. Believe cheap facilties manager thought it cost too much. Same cheap boss refused to have doorknobs in several old 13,200 bolt substations replaced with crash bars in case an electrician burnt his hands..Worse part one substation was 3 floors underground and had no walkie talkie or cell phone communication. A newer building substation was 4 floors under ground and 70' below grade but had excellent communication. They had 2 1750 HP chillers that were feed from 13,200 volts to a 20' long enclosure that contained a 13.2 KV to a 4,160 tramsformer that feed a VFD. I adked for over a year where are the Arc fault labels were. Said they were working on it. Told my boss that no equipment should be allowed to be started until labels are on them. Hope in the near future that the AHJ &/or electrical inspector refuse to do an inspection until proper labels are installed.
Have to be carefull when ultility company replaces an old transformer with an energy saving lower impedance. Avaiable short circuit current will be higher. In some cases this new short circuit current will be higher then the rating on switchgear.
I do not think that any single or 3 phase motor that is on a modern VFD would contribute to the available short circuit current due to input goes thru a rectifier. Was always told rectifiers only allow current flow in one direction similar to a check valve in plumbing.
I really appreciate your input. My mic is high quality, but my placement is flawed based on some limitations that I'm working around. I've been alternating with an overhead mic stand and some other setups. The biggest thing I seem to be fighting (on the mic end) is the hum of my computer in proximity to the mic, but I've got a some filters ordered and a different arrangement in mind. Regarding echo and lighting, I've dropped a pretty substantial amount of money today on area rugs, drapes, and studio lighting. Hopefully I can have the issues resolved in a week or so. I really do appreciate your feedback (no pun intended), thanks a bunch!
When you work with DC power systems (batteries), you don't make the mistake of ignoring interrupt ratings. Sure, the fuse/breaker will have the primary rating in large print, but the more important (IMO) number is 1/10th the size just below it: the maximum current it can _interrupt._ Having seen a battery string short with a "lesser" fuse, sure the fuse "blew" -- the 400A rated wire broke -- but the fuse was instantly turned into a ball of plasma, and 50,000A continued to flow... between the bolts of where the fuse used to be. (the saving grace here was battery sag. after a few seconds, the voltage was too low to maintain the arc. otherwise, the string could (in theory) maintain that short for ~45s. of course, the wrench that caused the short would've been vapor long before that.) [For the record, I've seen a wrench "disappear" into a PDU -- telco battery room. As I recall, it didn't even set off an alarm, much less trip anything.]
Scary thing in my area the ultility company only installs a oversized fuse on 7.6KV primary side of their transformers. I had a service cable short out and almost burnt the house down because the primary fuse never cleared. Second thing I always thought was dangerous is lazy cheap ultility company only supplies 1 high voltage leg to their transformers when they have 3 phase on poles. They bond one of the primary transformer legs to case and center tap of 120/240 sevondary causing my copper water service & steel gas pipe to carry current back to transformer. They told me that it does not matter because they run a #6 aluminum wire down to a 8' ground rod at each pole that has a transformer on it. I know they do not follow the NEC but they get away with too much.
Hey I’m new subscriber from canyon country California Ryan I’m celecting money 💴 to buy your Tex books 📚 and 📀 I like your work you are doing I’ll spread all over the California tne work are doing
Very useful knowledge video. Thanks 👍
Thank you Ryan; another excellent class. . .
I'm here from the 100 Days of Article 100. I already watched this video, but i can't recall any of the information. Watching it a second time will probably help.
Great video Mr Ryan, it's so refreshing to watch this type of videos. We need more people like you in this field!!👏🏽
I always ordered & stocked 200 KIC on our 250 & 600 volt fuses 1 to 1200 amps just to be safe. At a large candy company that I worked at in the 1980 ' S they used renewable link fuses on everything on 480 volt equipment. A lot of 30 & 60 amp dafety switches were feed from 3000 buss duct. Little by little I got rid of the think they were only good for 10 KIC renewable fuses.
This was a fun video to watch. I was especially wowed by the 2/0 conductor getting the 16KA and just whipping the heck outta the whole area.
I'm enrolled in an electrical training program and we're watching the training DVD you were on with Mike Holt as part of the course. Glad I found your YT channel Ryan
Nice. I worked with Mike for over 10 years and did dozens of videos with him. Glad they are helping you!
Watching wire jump at high current solidifies the reason we torque, pull, loose, tighten…. terminals. Imagine a dead short on a branch circuit and the impact of a wire jump in the panel causing a wire to separate from a terminal or along an attic beam. Very interesting Ryan - thank you.
Definitely hope I can get labels on my two inside panels before inspection on Monday. I put AFC on service disconnect but not the other two.
Also I found the AFC for my service on the line drawing of the plans.
Here in Miami some inspector have had me find out from the utility company in writing because the plans did not show. Had to get the right breaker for the afc
Excellent presentation Ryan. I highly recommend this to anyone who is looking for help on this topic. I am sure it took an immense amount of preparation
Nice job Ryan. Appreciate all you are doing
At a very large hospital that I retired from while contractor was performing yearly cleaning & testing of 200 to 1200 amp 480 volt circuit breakers boss had us remove 6 or 8 spares from basement switchgear that had 40 or 42 KIA rating to a switcgear room on 10 th floor that all breakers were rated 65 KIA. We installed the spare 40 or 42 KIA breakers to what was all 65 KIA and never questioned it. Sharp Contractor picked this
Sorry fat fingers. Anyway they entire switvhboard is only rated as the liwest installed KIA breaker.
Amazing video. A much needed video from a great teacher.
exactly what i was looking for when it came to understanding available fault currents. thanks Ryan
Thanks for your effort, mister Ryan. God bless you.
You're the best!
Just got your books!
Great lessons here Mr. Ryan Jackson. Powerful video, great resources and tools. Thank you very much.
Thanks Felix, good to "see" you here!
@@RyanJacksonElectrical Here It is always a great professional experience. Sharing knowledge multiplies it. God bless you.
excellent! one of your BEST
One correction. @10:02, the fault current is 10613 A. Since it's a 3-ph system, you have to devide the answer by square root of 3.
That is single phase.
75KVA transformer doesn’t seem to be single phase. The fault current value is always per phase which is obtained by dividing by square root of 3.
Read the voltage. I have it circled. It is 120/240, single phase.
Once again…….quality info. Thank you.
In the example of the 300 KVA transformer at @18:41, you couldn't use the primary fuse of 80 amps on the nameplate to calculate fault current? I get 3600 amps if multiply 12470 x sqrt(3) x 80 / 480. But maybe they don't allow that because fuse might not blow in time, or weld itself together, or arc across the blown fuse etc. Still 3600 amps of 480v is one hell of an arc flash, enough to give someone being dumb the floor temperature challenge.
Do you know if there is any short circuit current requirement for splicing connectors like the Wagos or the 3M Scotchlok?
I have not found information about it, it seems to me that the connectors are very useful but not in industrial buildings where the short circuit currents could be considerable.
I will see what I can find out, but I would guess the rating is quite high. If you think about a terminal block (power distribution block), for example, the part that fails during a fault is not the terminal but the way the terminal connects to the plastic and the plastic connects to the enclosure. The fault doesn't melt the terminal, it rips the insulating material off the terminal or off the enclosure. I just don't see many failure points on the connectors you mention (but that is me speaking without looking into it deeper).
Thank you. Do you have a video about Series Rated vs. Fully Rated sistems, I would like to hear you opinion
Another great vid Ryan. Question at a 12 story building that I worked at all motors 5 HP & higher had VFD drives except for soft start on 200 HP soft start fire pump. Motors 60 HP & larger were on 18 pulse drives would this effect the motor thing on the Eaton calculator?
Yes, that would add fault current.
Great video. Is it code compliant to use fused disconnects upstream of equipment for short circuit protection on equipment with lower fault withstand ratings or is that not complaint with 110.10.
Yes, if properly rated. You would not have any selective coordination, however.
@@RyanJacksonElectrical thanks. Yeah this EV charger manufacturer only has an equipment rating of 5ka. Which basic is nothing. Just thinking of using peak let thru curves to show it is below 5 with a fuse. Thx
Thanks for the great videos! I have seen the after effects of cables jumping out of cable trays but never seen it before and dang that was cool!!!! I have never though of it as a magnetic issue causing it, just as a flow of electricity like water hammer.
Really good video.
very informative video Ryan, thanks! Do you know of any tools to calculate available fault current from mobile generators?
21:56 i kinda wonder why i got 26,544 amps for the fault current on the 750KVA, 3 phase 480volt secondary, 3.4% impedance example. i did 750kva ÷ 831 ÷ 0.034 = 26,544 amps
Great point. My example includes the 10% transformer impedance variation that I discuss while using the software. I really should have included that in the written narrative of the example.
@@RyanJacksonElectrical I think i figured out what you are saying. 750,000VA ÷ 831 ÷ (0.0306 which is 90% of 3.4%) = 29,494.35A available fault current.
@@elc2k385 Yep, exactly 💯
I'm confused. The future you are from say from t he transformer secondary the available short circuit current goes down while if I have it right from a long ago safety class the Arc Flash can be higher further from the transformer. Thanks for another informative vid.
The available fault current decreases the farther you get from the source. The incident energy is based on the voltage, available fault current, and (perhaps most importantly) the clearing time of the overcurrent device. Lower levels of fault current yield greater clearing times so the incident energy will vary greatly throughout the system. You really cannot just say that the incident energy will decrease the farther you get from the source.
@@RyanJacksonElectrical Thanks Ryan. Believe most electricians are more concerned about the Arc fault value in an existing large industrial setting to make sure they have the proper PPL. Diappointing to see most switchgear & panel boards still not labeled for Arc Flash rating. At the large hospital/research centets/ ambulatory building we took turns walking a company that wrote down every transformer and the panels they feed along with wire size and length of wire. Probably took over 60 hours over several months. After all said and done nothing got labeled. Believe cheap facilties manager thought it cost too much. Same cheap boss refused to have doorknobs in several old 13,200 bolt substations replaced with crash bars in case an electrician burnt his hands..Worse part one substation was 3 floors underground and had no walkie talkie or cell phone communication. A newer building substation was 4 floors under ground and 70' below grade but had excellent communication. They had 2 1750 HP chillers that were feed from 13,200 volts to a 20' long enclosure that contained a 13.2 KV to a 4,160 tramsformer that feed a VFD. I adked for over a year where are the Arc fault labels were. Said they were working on it. Told my boss that no equipment should be allowed to be started until labels are on them. Hope in the near future that the AHJ &/or electrical inspector refuse to do an inspection until proper labels are installed.
Hey Ryan, if I watch all these videos do I still have to do my UT continuing ED? 😆
@@caysonbaylor8055 am I missing something? Why would anyone want to hack an Instagram?
Have to be carefull when ultility company replaces an old transformer with an energy saving lower impedance. Avaiable short circuit current will be higher. In some cases this new short circuit current will be higher then the rating on switchgear.
I do not think that any single or 3 phase motor that is on a modern VFD would contribute to the available short circuit current due to input goes thru a rectifier. Was always told rectifiers only allow current flow in one direction similar to a check valve in plumbing.
Great video, consider getting a higher end mic, some studio lights and adding some sound matts for the echo to your office.
I really appreciate your input. My mic is high quality, but my placement is flawed based on some limitations that I'm working around. I've been alternating with an overhead mic stand and some other setups. The biggest thing I seem to be fighting (on the mic end) is the hum of my computer in proximity to the mic, but I've got a some filters ordered and a different arrangement in mind. Regarding echo and lighting, I've dropped a pretty substantial amount of money today on area rugs, drapes, and studio lighting. Hopefully I can have the issues resolved in a week or so. I really do appreciate your feedback (no pun intended), thanks a bunch!
@@RyanJacksonElectrical nice good luck for a y.t channel i know it's an investment.
MOM!! Ryan told me to open the transformer box!
LOL
When you work with DC power systems (batteries), you don't make the mistake of ignoring interrupt ratings. Sure, the fuse/breaker will have the primary rating in large print, but the more important (IMO) number is 1/10th the size just below it: the maximum current it can _interrupt._ Having seen a battery string short with a "lesser" fuse, sure the fuse "blew" -- the 400A rated wire broke -- but the fuse was instantly turned into a ball of plasma, and 50,000A continued to flow... between the bolts of where the fuse used to be. (the saving grace here was battery sag. after a few seconds, the voltage was too low to maintain the arc. otherwise, the string could (in theory) maintain that short for ~45s. of course, the wrench that caused the short would've been vapor long before that.)
[For the record, I've seen a wrench "disappear" into a PDU -- telco battery room. As I recall, it didn't even set off an alarm, much less trip anything.]
That's one of the problems. The fuses will work...until you need them.
Scary thing in my area the ultility company only installs a oversized fuse on 7.6KV primary side of their transformers. I had a service cable short out and almost burnt the house down because the primary fuse never cleared. Second thing I always thought was dangerous is lazy cheap ultility company only supplies 1 high voltage leg to their transformers when they have 3 phase on poles. They bond one of the primary transformer legs to case and center tap of 120/240 sevondary causing my copper water service & steel gas pipe to carry current back to transformer. They told me that it does not matter because they run a #6 aluminum wire down to a 8' ground rod at each pole that has a transformer on it. I know they do not follow the NEC but they get away with too much.
Hey I’m new subscriber from canyon country California Ryan I’m celecting money 💴 to buy
your Tex books 📚 and 📀 I like your work you are doing I’ll spread all over the California tne work are doing