The primary voltage discount looks like free money on paper and it catches people out constantly.
The discount exists because the customer is taking service at primary voltage and therefore providing and maintaining the transformation equipment the utility would otherwise own. It is compensation for owning that asset and carrying its losses. It is not a reward for having a big service.
So the question is never "is this a large account." It is "who owns the transformer, and where is the metering point relative to it." I have seen accounts taking service at primary voltage, metered on the primary side, with a customer-owned transformer, that were never given the discount because nobody at the utility went looking. I have also seen the reverse — an auditor claiming the discount on a service where the utility owned the transformer, which went nowhere and cost the client credibility.
Before you raise it, get three things: the service configuration on the utility record, the metering point, and documentation of who owns and maintains the transformation equipment. A single-line diagram usually settles all three at once.
Also check whether the discount, where it applies, is stated as a percentage reduction, a separate rate schedule, or a loss adjustment factor applied to the metered quantities. All three exist depending on the utility, and they are worth materially different amounts.
The discount exists because the customer is taking service at primary voltage and therefore providing and maintaining the transformation equipment the utility would otherwise own. It is compensation for owning that asset and carrying its losses. It is not a reward for having a big service.
So the question is never "is this a large account." It is "who owns the transformer, and where is the metering point relative to it." I have seen accounts taking service at primary voltage, metered on the primary side, with a customer-owned transformer, that were never given the discount because nobody at the utility went looking. I have also seen the reverse — an auditor claiming the discount on a service where the utility owned the transformer, which went nowhere and cost the client credibility.
Before you raise it, get three things: the service configuration on the utility record, the metering point, and documentation of who owns and maintains the transformation equipment. A single-line diagram usually settles all three at once.
Also check whether the discount, where it applies, is stated as a percentage reduction, a separate rate schedule, or a loss adjustment factor applied to the metered quantities. All three exist depending on the utility, and they are worth materially different amounts.