51 entries.

Could you assist me in determining if my PV solar panel system has a safety issue involving a potential arc flash problem. I have investigated several papers on this subject and realize this is a complex voltage/current with complicated calculations beyond my complete understanding. My solar panel system design consist of two PV solar panels generating about 75VDC and 5.0ADC total directly connecting to an electric water heaters' 16ohm heating element through a 40 foot 16AWG cable. Again, my concern is do I have a safety issue here?

Any help via referals, informative articles, or experimental testing performed at these low DC voltages and low DC currents would be helpful.

If I get lucky with a response from you I am more than happy to discuss my somewhat original clever design to use existing setup involving minimum cost.

Thank you

David Lopez

[email protected]

808-868-3128

Any help via referals, informative articles, or experimental testing performed at these low DC voltages and low DC currents would be helpful.

If I get lucky with a response from you I am more than happy to discuss my somewhat original clever design to use existing setup involving minimum cost.

Thank you

David Lopez

[email protected]

808-868-3128

Sir Ver,

Thank you for your valuable information and tutorials

Thank you for your valuable information and tutorials

hi engr ver,

where can I find IEC 6909 standard for short circuit calculations? I hope I can get a copy. thanks sir

where can I find IEC 6909 standard for short circuit calculations? I hope I can get a copy. thanks sir

hi sir,

can I ask if there is a short circuit calculations under no load condition. thank you sir

can I ask if there is a short circuit calculations under no load condition. thank you sir

Hye Ver.

Can I habve your email?

Need to attach some examples of source impedance calculation.

Can I habve your email?

Need to attach some examples of source impedance calculation.

Dear Engrs,

What is the standard height of switches?

thank you and regards,

What is the standard height of switches?

thank you and regards,

Tanung lang po... pwede po mag tap ng cable sa common busbar ng mvsg (I mean dun talaga mag tap to get power). Sa pagkakaalam ko kasi medyo delikado kasi yun, unang una kaya nga naka enclosed ang busbar compartment is for safety..

Refer to https://pangonilo.com/tutorials/mva-method/short-circuit-study

SC MVA = KV2 / Z

From IEE regulation Table 4D2B (column 3, 4)

Cable 120mm2:

(mV/A/m)r = 0.33mOhm

(mV/A/m)x = 0.135mOhm

Assume:

R = (0.33mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0057 ohm

X = (0.135mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0023 ohm

Z= Sqrt (R2 + X2)

SC MVA = KV2 / Z = (0.4 x 0.4) / 0.00614 = 26

Should R and X divided by Sqrt (3) for SC MVA calculation please?

SC MVA = KV2 / Z

From IEE regulation Table 4D2B (column 3, 4)

Cable 120mm2:

(mV/A/m)r = 0.33mOhm

(mV/A/m)x = 0.135mOhm

Assume:

R = (0.33mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0057 ohm

X = (0.135mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0023 ohm

Z= Sqrt (R2 + X2)

SC MVA = KV2 / Z = (0.4 x 0.4) / 0.00614 = 26

Should R and X divided by Sqrt (3) for SC MVA calculation please?

Hi Good day!

I've been programming some relays, and now i found myself in difficulties understanding my new device. By principle i have an idea how it works but by computation i have some difficulties understanding it. My problem is the Distance Relay . I might understand the principle if i have some illustrations and sample problems with computation.

Hoping for your help and thank you in advance

I've been programming some relays, and now i found myself in difficulties understanding my new device. By principle i have an idea how it works but by computation i have some difficulties understanding it. My problem is the Distance Relay . I might understand the principle if i have some illustrations and sample problems with computation.

Hoping for your help and thank you in advance

Hi Ver! I would like to verify if I have to size the 200A main switch ampere fuse rating of a transformer at 150KVA, 600V primary and 208V primary with a secondary load of 59kW. Do I have to size the fuse base on the transformer primary overload capacity or the feeder load of 59kW? Thanks.

Hi may question lang po. Anu difference ng. 400v/230v system and 460v/230v syatem

good day po,

Engr. Ver may training pa kayo sa scada? email me po kung meron pa thanks. [email protected]

Engr. Ver may training pa kayo sa scada? email me po kung meron pa thanks. [email protected]

Engr. Ver good morning po. Tanong ko lng po, ilan po ang minimum allowable distance ng poste ng meralco sa property line ay any part ng bahay ko. Salamat po.

Chito Serrano

Chito Serrano

Where to find a book?

Philippine Electrical Codes Volume 1

Thanks,

Philippine Electrical Codes Volume 1

Thanks,

tanung lang po

1.0 anu po ang maximum allowable na ampacity sa switchgear (low voltage).

2.0 maximum acb rate is 6300A for low voltage application, anupong susunod na device lets say for 10000A protection, are there any.

maraming salamat po

1.0 anu po ang maximum allowable na ampacity sa switchgear (low voltage).

2.0 maximum acb rate is 6300A for low voltage application, anupong susunod na device lets say for 10000A protection, are there any.

maraming salamat po

Good day Sir,

I have a problem with VSD failures at one of my sites (a shopping centre). The system consists of an 11kV incomer and many 11kV / 400V distribution transformers.

Power readings indicate an imbalance of voltages on the 11kV incomer terminals.

Where should I start for diagnoses?

I have a problem with VSD failures at one of my sites (a shopping centre). The system consists of an 11kV incomer and many 11kV / 400V distribution transformers.

Power readings indicate an imbalance of voltages on the 11kV incomer terminals.

Where should I start for diagnoses?

good day sir,

ask ko lang po if pwede po bang pagsamahin ang set of wires from load and line side sa iisang conduit na RSC?

salamat po

ask ko lang po if pwede po bang pagsamahin ang set of wires from load and line side sa iisang conduit na RSC?

salamat po

Good day Engr. Ver!

just passed by to say thank you..i found your site few years ago and your site really help a lot..

God bless..

just passed by to say thank you..i found your site few years ago and your site really help a lot..

God bless..

I am having trouble correlating motor class insulation and its relation to B rise and F rise. For example, can you have a 65 degree ambient with Class F insulation and meet B rise, why or why not?

Sir Ver

Good day, im working in hospital facility, voltages in our distribution line are L1N=115v, L2N=120v, and L3N=220v, but the line to line voltage is 230v, QUESTION-what do you think is the problem. any suggestion or recommendation please. thanks

Good day, im working in hospital facility, voltages in our distribution line are L1N=115v, L2N=120v, and L3N=220v, but the line to line voltage is 230v, QUESTION-what do you think is the problem. any suggestion or recommendation please. thanks