Well that depends on how you define secure.
I assume your embed code is an iframe which means that you are putting something not under your control (that could in theory always change into something malicious) into your site. This isn’t 100% secure itself. That is why esc_html
strips that out.
The question you have to ask yourself is how much of a risk this is regarding the person who has the right to change this field.
But maybe there is an alternative if the embed you are using is from a site that has oEmbed support in WordPress.
Then you can easily embed it using wp_oembed_get. This still puts an iframe from somewhere else into your site, but at least it doesn’t allow arbitrary HTML or JS.
If you add some more info about what embed code we are actually talking about I might even be able to provide an example.