Chris Send me a copy too or the link if you have one
Thanks Bill Hoffer ---- Chris Anderson <cander...@borregosolar.com> wrote: > I also have a link to a great FLUKE document on the insulation testing. > (meggering wires) > I can send it to you offline if you would like a copy. > > -Chris Anderson > Chief Technology Officer > Resources Group > C: 603-732-2411 > Borrego Solar Systems > > From: re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Chris Anderson > Sent: Wednesday, September 16, 2009 2:19 PM > To: RE-wrenches > Subject: Re: [RE-wrenches] Insulation testing > > I would like to put forward our commissioning test procedures with regard to > voltage and insulation testing for comment and to share if others are trying > to tighten up their commissioning procedures. I would love to hear Bill's > feedback and any input others might have into our process and areas where we > might be exposed. > Thanks in advance for your comments. > > Sequence and Procedures for > Quality Assurance Testing and System Commissioning > > Quality Assurance Testing > o Source Circuit Testing - Voltage and continuity to ground of all strings > · Test conditions: > § Testing to be done at the combiner boxes > § Modules are connected to the home runs > § Positives are landed on the fuse block, but fuses are not yet installed in > the CB > § Negatives are cut to length and labeled but not landed in the CB > § Ground is connected in a continuous path to the racking and modules and > is landed in the CB > · Test > § Check for voltage between each positive and all negatives - record > voltages for each strings and confirm no voltage between strings of different > numbers, simultaneously verify polarity as recording voltages > § Check for voltage between each positive and ground - record voltage > (should be 0) > § Check for voltage between each negative and ground - record voltage > (should be 0) > § Complete the first half of the combiner box commissioning worksheet - > noting weather, time of day etc. > · After the test is complete > § Each negative can be landed on the negative block in the CB > § Test continuity of fuses and insert into holders - DO NOT CLOSE > > o Output Circuits - Insulation testing of wires from CB to Inverter and > verification of polarity > · Test conditions: > > * Testing to be done at the inverter > * All wires are run in conduit, cut to length, labeled, spliced if > applicable and conduit covers are on from combiner through to inverter > * Only the ground wires are landed in both the CB and the inverter > * The GFDI fuse is removed from the inverter > * All conductors are taped off at the opposite end of where the > Megohmeter will be attached and are safely isolated to prevent touching of > anything and in a safe position to be energized > · Test > > * Megger test all wires to ground at 1000Vdc > * Megger test all wires that share a conduit at any point in the > system to each other at 1000Vdc > * record all values and troubleshoot any wires that have a reading > under 100 M Ohms corrected for Temp and humidity > · If under 100 M Ohms requires investigation and may require > replacement of the wire > · After the test is complete > > * Land the positive and negative at the combiner box > * Close one fuse holder at CB1 and close the integrated CB/rooftop > DC disconnect protecting the output of the CB > * test for voltage and polarity between the positive and negative > output circuits from CB1 at the inverter and verify that they are properly > labeled > * Open the CB/rooftop DC disconnect and then open the fuse holder in > CB#1 > * Verify that the voltage has bled down to zero then land the > positive and negative wires for this combiner box at the inverter > * Repeat steps for each CB until all polarity and wire locations are > identified and landed > * Once all the positive and negative wires from the CB's are landed, > if applicable test continuity of the fuses at the inverter disconnect and > insert into holders > > o AC Wiring Circuits - Insulation testing of wires from AC Tie in point > (POCC) to Inverter and verification of phasing > · Test conditions: > > * Testing to be done at the inverter > * All wires are run in conduit, cut to length, labeled, spliced if > applicable and conduit covers are on from AC Point of Connection through to > the inverter > * Only the ground wires are landed in both the Main Service Panel > and the inverter > * The GFDI fuse is removed from the inverter > * All conductors are taped off at the opposite end of where the > Megohmeter will be attached and are safely isolated to prevent touching of > anything and in a safe position to be energized > · Test > > * Megger test all wires to ground at 1000Vdc > * Megger test all wires that share a conduit at any point in the > system to each other at 1000Vdc > * record all values and troubleshoot any wires that have a reading > under 100 M Ohms corrected for Temp and humidity > · If under 100 M Ohms requires investigation and may require > replacement of the wire > · After the test is complete > > * Land the conductors in the inverter being sure to follow the > inverter manufacturer's guidelines for torque settings and use a permanent > marker to create a straight line across the screw indicating the proper > torque setting > * This test will likely be completed before the building shut down > to interconnect the system. Do not land the conductors at the AC tie-in > point until the panel has been properly de-energized > * After the Service Panel or tie-in point is de-energized, land the > conductors at the AC tie-in point. Be sure to follow the manufacturer's > guidelines for proper torque settings and use a permanent marker to create a > straight line across the screw indicating the proper torque setting. > > o Connection testing > · Test conditions: > > * Testing to be done at all locations > * All wires are landed > · Test > > * Test all wires for proper torque settings - refer to manufacturer > installation manual > * Physically tug on all wires for a visual inspection of loose > connections > NOTE - All conductors #4 and larger should be marked with a straight line on > the screw once they have been tightened to the appropriate setting > · After the test is complete > § Close all fuse holders at each combiner box > § Close all DC disconnects associated with each combiner box > > System Commissioning > o You are now ready to Commission the inverter > o Follow inverter manufacturer commissioning procedures > o Complete the balance of the combiner box commissioning worksheet, the > initial start up and inverter commissioning worksheet > > > · Imp Testing of source circuits > § Test conditions: > · Testing to be conducted at combiner boxes > · System is up and running > § Test > · At each combiner box, check for operating current of each string by > placing a clamp meter around each positive source circuit - record the value > on the combiner box commissioning worksheet > · Simultaneously record the irradiance value at the plane of the > module for the strings of which you are testing > · Repeat for all strings in the combiner box > > § Imp Testing of output circuits > § Test conditions: > · Testing to be conducted at the inverter > · System is up and running > § Test > · Check for operating current of each CB output circuit by placing a > clamp meter around each positive wire - record the value on the inverter > commissioning worksheet > · Simultaneously record the irradiance value at the plane of the > representative modules for the combiner box of which you are testing > · Repeat for all output circuits from each combiner box > > > > -Chris Anderson > Chief Technology Officer > Resources Group > C: 603-732-2411 > Borrego Solar Systems > > From: re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of David Palumbo > Sent: Monday, September 14, 2009 10:58 PM > To: 'RE-wrenches' > Subject: Re: [RE-wrenches] Insulation testing > > I'd like to see if we can complete the thread on insulation testers > (Meggers). Below is a copy of Bill Brooks last posting on this subject from > several weeks ago. > > Bill says the keys are to use the tester and in "performing the tests > properly and safely which requires test procedures". What are the proper > testing procedures? We have a Fluke 1503 and the information that came with > it is not very helpful in setting up a testing procedure. The DVD that came > with it is more of a sales tool on why you should have the tool. We already > have the tool. We want to know how to use the tool. Can anybody give advice > on this? > > > << I bought two insulation testers (Megger is a brand name) in April. A used > Fluke 1520 off Ebay for $275 and a new inexpensive (cheap) insulation tester > on Amazon (Electronic Specialties 550 Insulation Tester for $162). Both work > fine. The Fluke has better accuracy that I need for very specialized "field > wet resistance testing" (FWRT). However, the cheap tester works great for > finding faults in conductors and severe faults in modules. > > I bought both to determine if a cheap meter would work and the answer is > YES. The key is performing the tests properly and safely which requires test > procedures. The other key to actually use the tester. Several people own > these devices, but never use them. They should be used on every installation > after the wire is installed to determine if any wire damage is visible to > the tester. Even though this will not solve all field mistakes, it will > catch the marginal problems that may be too small to be detected by the GFP > circuit in the inverter. > > Bill. >> > > > David Palumbo > President, Independent Power LLC > 462 Solar Way Drive, Hyde Park, VT 05655 > NABCEP Certified > www.independentpowerllc.com > (802) 888-7194 > _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
