How to Choose an APC Smart-UPS SRT Battery Extension Cable

If an APC Smart-UPS On-Line SRT battery pack has to sit farther from the UPS, the part to identify is the external-battery extension kit for that exact SRT family. A standard DC cable with matching-looking connectors is not an equivalent substitute. These links carry the battery connection and, depending on the kit, battery communications; the ground connection is a separate safety requirement. Schneider Electric's installation instructions name five-metre cable kits SRT002, SRT003, SRT009, SRT010 and SRT013 and assign them to different SRT capacities.

The first decision is therefore not "how many feet do I need?" Record the UPS model number, its SRT rating, and the model of every external battery pack (XLBP). Then match the cable model to the table below. If the label is missing or the UPS and pack belong to different SRT families, stop and check the product manual or Schneider support before ordering. A cable seller's phrase such as "APC UPS battery cable" does not establish compatibility.

Read the full model label rather than using a nominal capacity from memory. "SRT 3000" identifies a family, but regional suffixes and generation details can affect the correct pack or accessory. Keep a photo of the UPS identification label and battery-pack label in the purchase record. When equipment is installed in a rack, the model sticker may be on the rear or side panel; use the manual's identification page instead of moving energised equipment just to read it. If your label says SRT but the proposed extension kit model is not listed in the manual for that UPS, treat the match as unresolved.

Match the cable code to the UPS family

APC's extension-cable model codes track the UPS family and battery bus. Schneider Electric describes SRT002 for 5 and 6 kVA systems, SRT003 for 8 and 10 kVA systems, SRT009 for 2200 VA units, SRT010 for 3000 VA units, and SRT013 for 1000 and 1500 VA units. Manufacturer product listings specify the corresponding DC battery voltages as 192 V, 192 V, 72 V, 96 V and 48 V respectively. The rating on your UPS label and its manual are the controlling references; the voltage is a cross-check, not a way to infer connector compatibility by itself.

Five metres is the documented length; plan the route before you buy

The APC installation sheet identifies these as five-metre extension-cable kits. Retailer titles often call them 15-foot cables. Five metres converts to about 16.4 feet, so those labels are close marketing descriptions rather than mathematically identical lengths. Use the manufacturer kit documentation when defining the part, and measure the installed route in the room before ordering.

Measure along the path the cable will actually follow: from connector to connector, around rack sides and through cable-management points. Include enough slack to avoid pulling on the connector or sharply bending the cable, but do not leave a coil where it can obstruct a rack door, ventilation path, or service access. Record the required route length and ask the seller to confirm the exact APC model code and physical cable length on the quotation. If five metres will not reach, do not join two extension kits unless Schneider's documentation for that exact system explicitly permits it.

Check the conditions along that route as well. The cable should not be trapped under a rack foot, pressed against a sharp metal edge, or routed where routine battery-module replacement will snag it. Keep it away from moving doors and maintain the service access required by the equipment installation manual. If the cable must cross a doorway or a different room, measure the real path and have the site's electrical or facilities team approve the protection and routing method. A tape-measure distance across the aisle is not the installed cable length.

Schneider's FAQ says only one extension cable is permitted in an installation, whether it is placed between the UPS and an external pack or between two external packs. This is an important limit: it is not permission to extend every link in a chain. Multiple battery packs may be connected in the manufacturer's documented arrangement, but one approved extension cable is the stated maximum.

Sketch the intended layout before submitting an order: UPS, XLBP units, standard pack-to-pack links, and the single extension point. Mark where the five-metre lead would sit. A drawing exposes two common procurement mistakes early: ordering an extension cable for each battery pack, and buying a longer cable while assuming the entire chain can be lengthened. If the proposed route requires more than one extension or a cable longer than the documented kit, the layout needs manufacturer confirmation before a purchase order is released.

Understand which parts are in each kit

The five-metre installation sheet lists one battery and communications extension cable, screws and a ground cable for SRT002, SRT009, SRT010 and SRT013. SRT003 differs: its package list separates the extension power cable, communications cable and ground cable. That difference changes the installation checklist. A listing that says "SRT003 cable" but shows only a power lead has not shown the whole kit.

Before purchase, ask the supplier to photograph the labels and all included parts together. For SRT003, request confirmation that both the power cable and communication cable are included, along with the ground lead required by the installation. For the other kits, confirm that the combined battery and communications cable and the ground cable are present. Part counts, screw quantity and packaging can vary by revision or region, so compare the exact current contents with the kit's installation sheet rather than assuming a marketplace photo is complete.

Clarify whether the offer is a complete extension kit or a single replacement component. A warehouse may list a power lead, communication lead, ground strap or older surplus accessory under a broad "battery cable" title. Those pieces do not automatically replace a complete kit. Record the seller's exact stock number and ask whether the quoted part number is printed on the product, its original package, or only on the seller's invoice. If the seller cannot distinguish the kit from an individual lead, do not purchase it for a critical system based on a product photograph alone.

Install the cable in the right direction

Turn the system off and follow the UPS and external battery-pack manuals for the specific model. The battery bus can present a serious shock hazard even though it is DC. Do not open battery modules, improvise a connector, or rely on cable colour as proof of polarity or direction. If your site's procedure requires a qualified service technician, use one.

APC's troubleshooting guidance makes the direction of the battery connection explicit: connect the battery pack's Battery Output cable to the UPS or next pack's Battery Input. Never connect Battery Input to Battery Input. The reversed arrangement can trigger "Battery Sys Error - 0100." The installation diagram and port labels take priority over assumptions based on cable orientation. Secure the specified ground connections between the UPS, battery pack or packs, and the mains grounding system.

Do not treat the thick SRT003 cable as the whole job. APC lists the power extension, communications lead and ground lead separately, and the diagram assigns each its own route. The communications connection is easy to overlook because it is a smaller lead beside the battery cable. Trace it to the labelled port before closing the rack; make sure the ground lead is fastened at both ends and no wire is caught behind a rail.

Check the installation before returning the UPS to service

After restoring the covers, use the startup steps for the installed UPS rather than a generic restart sequence. The useful check is what the unit reports about its external battery configuration and whether a cable or pack alarm remains. APC's troubleshooting note directs the reader to inspect secure battery-plug connections when a connection message appears. Any self-test should follow the same model's manual, since an instruction written for one SRT capacity may not apply to another.

If the pack is absent from the UPS status, save the alarm text before doing anything else. Write down both model numbers and the extension-kit code; this prevents support from diagnosing the wrong combination. Any physical inspection comes after the shutdown and isolation steps in the manuals. At that point, compare the connector labels with the diagram, check the SRT003 communications lead if fitted, and confirm the ground path. A photo of the rear panel, with the model labels in the same service record, is more useful than a note that says only "battery cable checked."

A recurring battery-system error does not by itself prove that the extension cable is defective. The same symptom can point to the connection, the pack, its communications path, or configuration. Keep the error history, then follow APC's diagnostic steps for that precise UPS and battery pack. Do not alter the installed pack count simply to make the warning disappear; the count affects the runtime information the UPS reports. If the prescribed checks do not resolve it, hand the recorded models and event text to service.

Equipvia may earn a commission from qualifying purchases through this link. The link resolved to Product ID 1601969992676 during review. CPS resolution does not verify the seller's technical claims, the kit contents, affiliate eligibility, or commission attribution. Check the actual selected variant and current terms before ordering.

The listing's title ties the cable to SRT002 and describes a 15 ft extension, which matches the 5/6 kVA family in the APC table. It does not show the ground cable, the packaging label, or whether the item is new APC stock, surplus, or an aftermarket build. Confirm all three before using it on a live battery system, and check that the quoted length is the documented five metres rather than a rounded imperial figure.

What to ask a seller before placing an order

A SRT3000 order shows why the model number alone is not enough. APC's listing associates this family with SRT010 and a 96 VDC connection. That does not verify a third-party battery pack or a loose cable. Send the supplier the full UPS and XLBP labels and ask for a written answer naming the SRT kit, its length and everything in the box. If the offer is SRT003, have the quote call out the power lead, communications lead and ground cable separately. It is easier to clear up a missing component before the order ships.

Treat a marketplace title as a search term, not proof. Before paying, check that the quote and eventual invoice carry the same part number. Ask whether the cable is new APC stock, surplus, or an aftermarket build; the distinction matters when you later need to reorder or troubleshoot. For an aftermarket assembly, request its maker's drawing. It should identify the UPS and pack models checked, plus pinout, polarity, communications conductors and grounding. A close-up photo may confirm the shell shape, but it cannot tell you how the conductors are wired.

For a site that keeps a spare, make the first approved delivery the reference. Photograph the package label and lay out every lead in the same frame; save the image with the UPS model, XLBP model and manual revision. When stock is replenished, receiving staff can compare the new carton before shelving it. If the supplier proposes a substitute or changes the source, ask for a fresh compatibility review rather than relying on the old approval. Similar-looking cables are difficult to tell apart once they are loose in a bin.

When a longer cable is not the fix

If the route on your rack drawing exceeds five metres, pause before looking for a joiner or a second extension. APC's installation sheet documents a five-metre kit, and Schneider's FAQ limits an installation to one extension cable. Ask APC or an authorised service provider to confirm a supported arrangement for the actual UPS and pack models. Sometimes the simplest option is to place the UPS and XLBP closer together. Check the installation manual first: the new position still has to meet its power, ventilation and service-clearance requirements.

Update the rack drawing after the cable is installed. Mark which pack is connected through the extension and record both equipment labels. The lead may disappear behind a cabinet or under cable management, where it is not obvious during the next battery replacement. A small note in the maintenance record can prevent a technician from unplugging the wrong link while tracing the battery chain.

A concise selection check

Before releasing the order, line up five things: the UPS label, the XLBP label, the SRT kit code, the measured cable route and the supplier's parts list. They should describe one compatible installation. During fitting, follow the port labels and APC diagram for Output-to-Input direction and grounding. If any one of those records conflicts with the others, hold the order and resolve the discrepancy with the manufacturer or service provider.