Reverse Current Protection on 8 Channel Relay Board


Our technicians applied reverse voltage to the inputs on the relays on our 8 channel ethernet relay board. Normal 12V was still applied to its power input side. But they are now saying the board won’t turn on. Would applying reverse current to the relays kill the board? Does the board have reverse current protection? Is there a jumper that would need to be set to recover the board? Is there a recovery mode at all?

If the board is fried, is there an easily replaceable component that can be swapped, or is the whole board toast?

Will NCD repair a board (with cost) if it was sent back?


Hi Will,

We will repair the board under warranty.

We manufacture several 8 channel relay boards. Can you tell us which board you purchased? Many of them have bridge rectifiers so they will still operate even if power is connected backwards. Boards without a bridge rectifier however would be damaged if power is connected backwards.

To return the board for warranty repair you can complete an RMA form here:

Thank you,

Hi Travis,

We had ordered Part #689860056329. The Ethernet module based 8channel relay board with the Type H relays. I will complete the RMA form shortly.