Client got new 480V service in March with what should be 800A service but bills seem way low. Nameplate shows 800:5 CTs but I think utility installed 400:5 and programmed meter for 800:5 ratio. SCE is fighting the meter test request saying installation is correct. Anyone dealt with this before? Gordon C.
CT Ratio Wrong on New Service - Utility Pushing Back on Test
Gordon - Very common issue on new commercial services. The multiplier error can run for months before anyone notices. You need to document the actual CT nameplate readings with photos and compare to the meter programming display. Most meters will show the programmed CT ratio in the setup menus. What does your load analysis show versus billed kWh? Randy D.
Load analysis shows we should be seeing about 45000 kWh monthly but bills show 22500 kWh average. That's exactly half which supports the wrong CT theory. Haven't been able to access meter programming yet - SCE locks their AMI meters pretty tight. Gordon C.
Had exact same issue with PGE last year. They installed 200:5 CTs but programmed for 400:5. Took three months and a formal complaint to get them to admit the error. Document everything and push for that meter test - they'll usually find the problem once they actually look. Kira J.
Check if the meter is reading primary or secondary values too. Sometimes the CT ratio is right but they have the meter set wrong for primary vs secondary metering. APS did that to us on a Schedule E-32 account. Sarah M.
Update: Finally got SCE to send a tech out. Turns out CTs are correct 800:5 but meter was programmed for 1600:5 ratio. Bill was showing half the actual usage for five months. Now fighting over back billing amount. Gordon C.
Good catch Gordon. The back billing issue is tricky - most tariffs limit how far back they can go but you'll want to review SCE's rules on utility error corrections. Usually it's 6-24 months maximum. Make sure they use correct rates for each historical period. Randy D.
What kind of back billing amount are we talking about? That could be a significant hit for five months of half billing. Hank B.
About $18,000 in additional charges. Client is not happy but at least we caught it before it went on longer. SCE is being reasonable about payment plan options. Gordon C.
Ouch on that back billing. We always recommend monthly load factor analysis on new services for exactly this reason. Catches multiplier errors before they become expensive. Craig P.
Is there any way to prevent this on new installations? Seems like something that should be caught during commissioning. Priya N.
Priya - Best practice is to witness the meter programming and verify CT ratios during initial startup. Many consultants skip this step but it's critical for avoiding these expensive errors. Also good to run a quick load test with known loads if possible. Randy D.
We had OGE do similar thing on 480V service in Tulsa. Took photos of everything during installation now - CTs, meter display, even the setup screens if they'll let us. Steve B.
Final update: Got the back billing worked out at $16,200 with 12 month payment plan. Client learned expensive lesson but at least it's resolved. Thanks everyone for the advice. Gordon C.