Prok DVS price list 2026

What the Prok DVS list covers

The list covers three groups, named on its cover: protection relays, the accessories that go with them, and meters. A protection relay watches the current — and in some designs the voltage — through current transformers, and trips the breaker when it sees a fault. It is the device that decides whether a fault is cleared, so it is chosen for its functions and settings first, and priced second.

How to read a protection relay line

Each line in the list is a model, and the model carries the details that change the price. Check each of these before you compare:

• Protection functions. Overcurrent and earth fault are the commonest pair — the 50/51 and 50N/51N functions in the standard numbering — and relays add others, from undervoltage to unbalance.
• CT secondary. Whether the relay takes a 1 A or a 5 A input, matched to the CTs that feed it.
• Auxiliary supply. The voltage that powers the relay, which must exist in the panel.
• Outputs and communication. The number of trip and alarm contacts, and any communication port.
• Mounting. Flush panel mounting and the cut-out it needs.

What to specify before asking for a price

A relay RFQ that gives only a description cannot be quoted in one pass. Send the details the relay depends on:

1. 01The protection functions the scheme requires, from the single-line diagram or the consultant's specification.
2. 02The CT ratio, secondary current and accuracy class at the relay. A protection relay needs a protection-class CT, such as 5P10 or 5P20, not a metering CT.
3. 03The auxiliary supply available, AC or DC, and its voltage.
4. 04The breaker it trips, and the voltage of that breaker's shunt trip coil.
5. 05Any communication the plant system needs.

Our post on the most common switchgear ordering errors explains why a metering CT on a relay is one of the eight errors that recur, and our post on the 20 most used electrical components lists the ratings to give for relays, CTs and meters.

What to price alongside the relay

A relay rarely works alone, and the parts around it are easy to leave off an order. Check which of these the scheme needs, and price them with the relay rather than at commissioning:

• the protection-class CTs, with the right ratio, class and burden;
• auxiliary or lockout relays where the scheme calls for them;
• test terminal blocks, so the relay can be tested without disturbing the wiring;
• the shunt trip on the breaker, at the voltage the relay's trip circuit uses;
• any communication cable or converter the plant system needs.

A relay is only as good as its settings

A protection relay arrives with default settings. Before the panel is energised, the settings for pickup current, time delay and curve must be applied from the protection study, and the relay should be tested by injection by a qualified engineer. Price the relay with that work in mind: the cheapest relay that cannot provide a function the study needs is not a saving.

List price, GST and discount

Check the terms printed in the list for its price basis. A list price is normally before GST, which is added to the seller's net rate; an MRP includes all taxes. Sellers quote a discount off the printed figure, and it varies with the quantity and the seller. Compare quotations on the same model, the same options and the same basis. Our guide to reading a switchgear quotation works through a comparison.

Buying genuine relays and meters

A protection relay is the last line of a protection scheme, so buy it through the maker's authorised channel and check what arrives against our guide to verifying genuine switchgear. For comparisons, the Elmeasure and Selec price lists are on this site too.

Questions about the Prok DVS price list