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73 entries.
bashir hussein bashir hussein wrote on February 7, 2019 at 7:17 PM
We have some 6.6kv cells which have been dismantled recently from a substation in which the European standard is used i.e.(6.6kv, 50Hz), now we are planning to install them in different plant where the American standard is used (4.16kv, 60Hz), please advice regarding the possibility of this installation.
Corazon Quintos Corazon Quintos wrote on January 15, 2019 at 11:43 PM
What is the philippine electrical code to data connection? Thank you
Admin Reply by: Ver Pangonilo
If I understand your question right, you might need to check these clauses

david lopez david lopez wrote on October 28, 2018 at 2:14 PM
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]
Admin Reply by: Ver Pangonilo
Your electric heater will draw a current from your solar panel at its peak of about 4.6A depending on the time of the day. Regarding your concern about possible arc-flash, a fault occurring at the terminal of your water heater will draw about 375A ideally. As you have not provided the technical specification of your panel, and with the minimal data you provided, I can assume that your solar panel will not be able to generate this amount of fault current. The incident energy will not be sufficient to produce an arc-flash.

IEEE 1584 can guide you on calculating arc-flash.
samuel s. adriatico samuel s. adriatico wrote on September 11, 2018 at 3:23 PM
Sir Ver,
Thank you for your valuable information and tutorials
Admin Reply by: Ver Pangonilo
My pleasure. Thank you
samuel s. adriatico samuel s. adriatico wrote on August 1, 2018 at 7:42 PM
hi engr ver,
where can I find IEC 6909 standard for short circuit calculations? I hope I can get a copy. thanks sir
Admin Reply by: Ver Pangonilo
The correct number for the standard is IEC 60909. Check IEC web store at https://webstore.iec.ch/publication/24100
samuel adriatico samuel adriatico wrote on August 1, 2018 at 7:31 PM
hi sir,
can I ask if there is a short circuit calculations under no load condition. thank you sir
Admin Reply by: Ver Pangonilo
Yes there is a no load short circuit calculation. There will be no load contribution to the total short circuit current.
Adam Adam wrote on July 31, 2018 at 3:54 PM
Hye Ver.
Can I habve your email?
Need to attach some examples of source impedance calculation.
Admin Reply by: Ver Pangonilo
Please send queries to this email: admin@pangonilo.com
Marlo Lamsen Marlo Lamsen wrote on June 18, 2018 at 1:29 PM
Dear Engrs,

What is the standard height of switches?

thank you and regards,
Admin Reply by: Ver Pangonilo
The PEC does not have a provision on the mounting height of switches. This means that it will be all up to the end-user whatever is convenient.
Joefrey Tanega Joefrey Tanega wrote on June 13, 2018 at 10:13 PM
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..
Admin Reply by: Ver Pangonilo
It is possible to connect a new feeder on the busbar on the condition that you need to:

Check the fault level on the busbar to ensure that you connect the right protective device and cable
Install a protective device just downstream the busbar
Ensure that you are competent to do the job else ask a competent Electrical practitioner to do the job for you.
TCK TCK wrote on April 5, 2018 at 9:13 AM
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
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?
Admin Reply by: Ver Pangonilo
Ensure that you are dealing with the correct voltage. Phase voltage is required to solve for the phase cable KVA. For three (3) phase, there are 3 cables so you need to multiply the KVa by 3 to get the total cable KVA.

For single phase, it will be a different calculation.
Jerome Jerome wrote on March 16, 2018 at 6:45 PM
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
Admin Reply by: Ver Pangonilo
The best way to understand how to program your distance relay is to refer to the user's manual. To understand the basics of distance relay, you could refer to the following

Ray Ray wrote on March 9, 2018 at 1:32 AM
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.
Admin Reply by: Ver Pangonilo
As per provision of the PEC. This is also similar to NEC provision (450.4 Autotransformers 600 Volts, Nominal, or Less). Autotransformers 600 Volts, Nominal, or Less.

(a) Overcurrent Protection. Each autotransformer 600 volts,
nominal, or less shall be protected by an individual overcurrent device
installed in series with each ungrounded input conductor. Such
overcurrent device shall be rated or set at not more than 125 percent of
the rated full-load input current of the autotransformer. Where this
calculation does not correspond to a standard rating of a fuse or
nonadjustable circuit breaker and the rated input current is 9 amperes
or more, the next higher standard rating shall be permitted.

The load need to be protected separately.
Alan Choa Alan Choa wrote on March 1, 2018 at 5:51 PM
Hi may question lang po. Anu difference ng. 400v/230v system and 460v/230v syatem
Admin Reply by: Ver Pangonilo
A 400/230V system is 3 phase. This is an IEC standard voltage while a 460/230V system is single phase. This is a NEC & PEC standard voltage
jasper jasper wrote on February 20, 2018 at 11:06 PM
good day po,
Engr. Ver may training pa kayo sa scada? email me po kung meron pa thanks. [email protected]
Admin Reply by: Ver Pangonilo
I am sorry to say, pero wala. Thanks for the enquiry
Dimas Serrano Dimas Serrano wrote on February 15, 2018 at 2:58 AM
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
Admin Reply by: Ver Pangonilo
Chito, kung ang pagbabasehan ay ang PEC, sa aking kaalaman ay walang nakasaad na minimum allowable distance from the property line. Pero meron itong provision on horizontal clearances of wires and cables for other structures is 1.5m (ref. PEC 2 - 2008 Clause Kaya nasa sa iyo na yun kung papayag ka na magtayo ang Meralco ng poste sa property mo.
Ella Ella wrote on December 20, 2017 at 1:16 PM
Where to find a book?

Philippine Electrical Codes Volume 1

Admin Reply by: Ver Pangonilo
You can buy it from IIEE (http://iiee.org.ph)
Joefrey Joefrey wrote on November 23, 2017 at 6:50 PM
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
Admin Reply by: Ver Pangonilo
It is best to consult Standards (IEEE, IEC, etc) for your question. In my designs, I used a maximum of 3200A ACB rating. Larger than that, there will be lots of issues concerning busbar sizes, temperature rise, etc.
shaun shaun wrote on October 30, 2017 at 10:33 PM
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?
Admin Reply by: Ver Pangonilo
The very first thing that you should do is to inform your power provider of the 11KV imbalance. I believe that the culprit is on their side. To protect your VSDs, you should install an undervoltage / single phasing protection relay on the VSD feeder breaker. This protection relay will trip if a voltage imbalance occurs protecting your VSD.
reagan ramos reagan ramos wrote on October 26, 2017 at 2:50 PM
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
Admin Reply by: Ver Pangonilo
Using good engineering practice, you should not combine line side conductors and load side conductors in a single conduit.
Erwin Directo Erwin Directo wrote on October 19, 2017 at 1:58 PM
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..
Admin Reply by: Ver Pangonilo
It's good to know you found my site helpful. Thanks for dropping by.