A fuse marked gPV and a fuse marked gG answer different application questions. Neither designation, by itself, approves a replacement for a particular circuit. Start the RFQ with the fuse location and the equipment it must protect, then require evidence for the exact offered part.
For a buyer, the useful comparison is not which category sounds more specialized. It is whether the supplier's documented application covers the proposed duty. This guide explains how to make that comparison before selecting a fuse or accepting a substitution.
What gPV and gG tell the buyer
gPV identifies a photovoltaic protection application. The public scope of IEC 60269-6:2010+AMD1:2021 CSV covers fuse-links protecting PV strings and arrays in equipment with circuit nominal voltages up to 1,500 V DC. The listing identifies edition 1.1 and the included November 2021 corrigendum. This is a scope statement from the public abstract; it is not a review of the complete standard or evidence that a particular product complies. IEC public publication record.
Eaton's Bussmann photovoltaic application guide, publication CA135004EN, August 2026, connects gPV to PV protection and explains the importance of operation with the limited fault currents available in PV systems. Its string and branch product discussion concerns those Eaton families. It does not make every fuse carrying a solar description suitable for every circuit in a solar installation. Eaton photovoltaic application guide, page 6.
gG denotes general-purpose protection, with the offered product's limits still applying. Mersen's Offset Tag fuse-link datasheet, DS-BSOTgG42-02-0624-EN, describes its covered gG range as general purpose and lists separate AC and DC ratings. This is an example of a documented gG range with DC ratings; it does not establish a DC rating for other gG products. Mersen Offset Tag gG datasheet.
Use the category as a screening field. Keep the manufacturer's full part number, application description and applicable rating documents beside it. A category name is not a complete purchasing specification.
Locate the fuse within the system
“Solar system fuse” leaves several different locations unresolved: the module string, combined array output, a storage branch or the inverter's AC output. Ask the designer to mark the proposed fuse position on a simple circuit diagram and identify the protected item.
There is a useful real example in the same Eaton catalogue. Its page 75 describes NH gG fuse-links for cable protection on the AC side of solar string inverters, with an 800 V AC rating. Their presence in a photovoltaic catalogue does not establish suitability for its DC string circuits. That application distinction belongs to the listed Eaton products and edition. Eaton AC-side NH gG section.
A procurement rule follows: record both the overall equipment description and the local circuit function. A catalogue heading can help find candidates, but the offered part's documentation must close the application question.
Treat a battery branch as a separate evidence request
Adding storage to a PV project should trigger a separate application review for the battery branch. A gPV designation is evidence about a PV application category; it is not, on its own, a battery-protection approval. Equally, the words general purpose do not establish that an offered gG fuse meets the battery circuit's requirements.
Ask for the manufacturer's documented battery application or a technical assessment identifying the exact part, circuit conditions and limitations. Provide the operating modes, source connections and the engineer's protection requirements. A reply that merely repeats the project label leaves the location-specific question unanswered.
This is an evidence boundary, not a blanket ban on a category. The responsible engineer should decide suitability from the applicable product data and system review. Record that decision against the particular circuit and document revision so it cannot silently become approval for every fuse position.
Build an application evidence register
Use one RFQ line per distinct fuse duty. The following worksheet is an original purchasing aid, not a table copied from a standard or a manufacturer specification.
On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.
| RFQ field | Buyer supplies | Supplier evidence to request |
|---|---|---|
| Circuit identity | Diagram reference, fuse position, protected item | Confirmation of the proposed application |
| Source and operating modes | PV, battery or other source; operating configurations | Stated scope and excluded conditions |
| Fuse identity | Approved reference, if one exists | Manufacturer, series, complete part number and category |
| Application basis | Required protection function | Applicable datasheet, application note and document revision |
| Electrical review | Engineer's voltage and fault-duty requirements | Part-specific data for those conditions |
| Substitution control | Mandatory requirements and review owner | Differences, supporting evidence and approval needed |
Use the DC fuse voltage and interrupting-capacity guide to develop the electrical-review line. Category screening does not replace that work.
Request a short evidence reference in each response: document title, revision, page and matching part-number entry. A folder containing numerous certificates is less useful when no one has identified which document supports the offered application. Keep manufacturer declarations distinct from the buyer's acceptance decision.
Compare three hypothetical replies
Consider an invented purchasing exercise with two positions: F1 protects a PV string, and F2 protects a battery branch. No actual ratings, project approval or supplier performance are implied.
Supplier A offers one gPV part for both positions and attaches a PV-string datasheet. That document may support further review of F1, but it has not established F2's application. Ask A for the missing battery-specific assessment; do not copy F1's evidence status across the two rows.
Supplier B offers a gG part for F2 and provides a product sheet showing DC ratings. This resolves a different question from application suitability. B must still connect the proposed part and its stated protection function to F2's requirements. A DC entry alone should not close the application review.
Supplier C provides separate proposals, identifies the relevant application documents and lists an unresolved operating-mode limitation for F2. Its reply is easier to review because the gap is visible. That does not make C's part automatically acceptable: the engineer must resolve the limitation before release.
The comparison separates document completeness from technical acceptance. Ask each supplier to close the specific missing link. Do not rank the replies merely by the number of attachments, the category label or the apparent breadth of a catalogue claim.
Close substitutions before comparing the final offer
Describe unresolved items precisely: missing part identity, missing application scope or a documented mismatch. A missing document calls for evidence; a mismatch calls for a revised proposal or an engineering decision. Giving both the label “pending” can hide the action needed.
Once the application is accepted, retain the original proposal, revised evidence and approval reference together. Changes to the series, suffix, category or stated application should reopen the relevant review. Do not let “equivalent fuse” become an unrestricted substitution term.
Application acceptance also leaves other reviews to complete. The DC fuse coordination guide addresses operating behavior and protection relationships. Fit, holder conditions and the final assembly remain part of the selected product's review.
For commercial comparison, request price and timing against the same accepted scope and list deviations separately. A lower quotation with unresolved application evidence is an incomplete offer, not a demonstrated saving. The SINAWATTS product catalogue can provide inquiry context; the supplier's reply must establish the actual offered configuration.
Send an application-specific RFQ
Send a DC fuse RFQ with the circuit diagram, fuse positions, operating modes and requested evidence register. Ask for exact proposed parts, application limits and separately stated commercial terms.
Buyer FAQ
Can a gPV fuse automatically replace a battery fuse?
No. The category alone does not establish suitability for a battery branch. Request product-specific application evidence and an engineering review of the proposed circuit conditions before accepting the replacement.
Does gG mean a fuse is suitable for every DC circuit?
No. Check the offered part's documented DC ratings and application scope. The Mersen range cited above is a specific example with DC data, not an authorization for every gG product or duty.
Is a fuse listed in a solar catalogue necessarily for the DC side?
No. The cited Eaton guide includes gG products intended for inverter AC-side cable protection. Identify the local circuit position and read the product entry rather than relying on the catalogue title.
What should a supplier provide for an equivalent replacement?
Request the complete replacement identity, category, applicable document revisions and a list of differences from the approved part. Keep application, electrical, coordination and assembly decisions traceable, and close unresolved differences before purchasing release.